{
  "title": "Elimination Method (Pair of Linear Equations) - Grade 10 CBSE",
  "total_questions": 100,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "Solve by elimination: x + y = 5 and x - y = 1", "options": {"A": "x = 3, y = 2", "B": "x = 2, y = 3", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 2, "difficulty": "easy", "question": "Solve by elimination: 2x + 3y = 7 and 2x - 3y = 1", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 2", "C": "x = 3, y = 1/3", "D": "x = 4, y = -1/3"}, "correct_answer": "A"},
    {"id": 3, "difficulty": "easy", "question": "Solve by elimination: 3x + 2y = 11 and 3x - 2y = 1", "options": {"A": "x = 2, y = 2.5", "B": "x = 3, y = 1", "C": "x = 4, y = -0.5", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 4, "difficulty": "easy", "question": "Solve by elimination: 5x + 2y = 16 and 5x - 2y = 4", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 0.5", "C": "x = 1, y = 5.5", "D": "x = 4, y = -2"}, "correct_answer": "A"},
    {"id": 5, "difficulty": "easy", "question": "Solve by elimination: x + 2y = 3 and 2x + 4y = 6", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = 0.5", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "C"},
    {"id": 6, "difficulty": "easy", "question": "Solve by elimination: 2x + y = 5 and 4x + 2y = 10", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 3", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "C"},
    {"id": 7, "difficulty": "easy", "question": "Solve by elimination: 3x - y = 2 and 6x - 2y = 5", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = 4", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "D"},
    {"id": 8, "difficulty": "easy", "question": "Solve by elimination: x + 3y = 7 and 2x + 6y = 13", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = 1", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "D"},
    {"id": 9, "difficulty": "easy", "question": "Solve by elimination: 2x + 5y = 9 and 3x + 5y = 11", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 1.4", "C": "x = 3, y = 0.6", "D": "x = 4, y = 0.2"}, "correct_answer": "A"},
    {"id": 10, "difficulty": "easy", "question": "Solve by elimination: 4x + 3y = 10 and 4x - 3y = 2", "options": {"A": "x = 1.5, y = 4/3", "B": "x = 2, y = 2/3", "C": "x = 1, y = 2", "D": "x = 3, y = -2/3"}, "correct_answer": "A"},
    {"id": 11, "difficulty": "easy", "question": "Solve by elimination: 3x + 4y = 10 and 3x - 2y = 1", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 1.75", "C": "x = 3, y = 0.25", "D": "x = 4, y = -0.5"}, "correct_answer": "A"},
    {"id": 12, "difficulty": "easy", "question": "Solve by elimination: 5x + 2y = 12 and 3x + 2y = 8", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 3.5", "C": "x = 3, y = -1.5", "D": "x = 4, y = -4"}, "correct_answer": "A"},
    {"id": 13, "difficulty": "easy", "question": "Solve by elimination: 2x + 3y = 8 and 5x + 3y = 14", "options": {"A": "x = 2, y = 4/3", "B": "x = 1, y = 2", "C": "x = 3, y = 2/3", "D": "x = 4, y = 0"}, "correct_answer": "A"},
    {"id": 14, "difficulty": "easy", "question": "Solve by elimination: 4x + 5y = 14 and 4x + 3y = 10", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = 1.2", "C": "x = 3, y = 0.4", "D": "x = 4, y = -0.4"}, "correct_answer": "A"},
    {"id": 15, "difficulty": "easy", "question": "Solve by elimination: 3x + 2y = 5 and 2x + 2y = 4", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = -0.5", "C": "x = 3, y = -2", "D": "x = 4, y = -3.5"}, "correct_answer": "A"},
    {"id": 16, "difficulty": "easy", "question": "Solve by elimination: x + 2y = 4 and 2x + 4y = 8", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 1.5", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "C"},
    {"id": 17, "difficulty": "easy", "question": "Solve by elimination: 2x + y = 3 and 4x + 2y = 7", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = -1", "C": "Infinite solutions", "D": "No solution"}, "correct_answer": "D"},
    {"id": 18, "difficulty": "easy", "question": "Solve by elimination: 3x + 5y = 16 and 3x - 5y = 4", "options": {"A": "x = 10/3, y = 6/5", "B": "x = 2, y = 2", "C": "x = 3, y = 1.4", "D": "x = 4, y = 0.8"}, "correct_answer": "A"},
    {"id": 19, "difficulty": "easy", "question": "Solve by elimination: 7x + 3y = 13 and 7x - 3y = 1", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = -1/3", "C": "x = 3, y = -8/3", "D": "x = 4, y = -5"}, "correct_answer": "A"},
    {"id": 20, "difficulty": "easy", "question": "Solve by elimination: 6x + 2y = 14 and 6x - 2y = 2", "options": {"A": "x = 4/3, y = 3", "B": "x = 2, y = 1", "C": "x = 3, y = -2", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 21, "difficulty": "medium", "question": "Solve by elimination: 2x + 3y = 13 and 5x - 4y = -2", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 22, "difficulty": "medium", "question": "Solve by elimination: 3x + 2y = 11 and 2x + 3y = 4", "options": {"A": "x = 5, y = -2", "B": "x = 4, y = -1", "C": "x = 3, y = 1", "D": "x = 2, y = 2.5"}, "correct_answer": "A"},
    {"id": 23, "difficulty": "medium", "question": "Solve by elimination: 4x + 6y = 15 and 6x - 8y = 14", "options": {"A": "x = 3, y = 0.5", "B": "x = 2, y = 1.17", "C": "x = 4, y = -0.17", "D": "x = 1, y = 1.83"}, "correct_answer": "A"},
    {"id": 24, "difficulty": "medium", "question": "Solve by elimination: 7x - 2y = 3 and 11x - 3y = 5", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = 5.5", "C": "x = 3, y = 9", "D": "x = 4, y = 12.5"}, "correct_answer": "A"},
    {"id": 25, "difficulty": "medium", "question": "Solve by elimination: 5x + 3y = 9 and 2x - 5y = 17", "options": {"A": "x = 3, y = -2", "B": "x = 2, y = -1", "C": "x = 4, y = -3", "D": "x = 1, y = 0"}, "correct_answer": "A"},
    {"id": 26, "difficulty": "medium", "question": "Solve by elimination: 0.2x + 0.3y = 1.3 and 0.4x + 0.5y = 2.3", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 27, "difficulty": "medium", "question": "Solve by elimination: 3x/4 + 2y/3 = 5 and 5x/2 - 3y/4 = 7", "options": {"A": "x = 4, y = 3", "B": "x = 3, y = 4", "C": "x = 2, y = 6", "D": "x = 6, y = 2"}, "correct_answer": "A"},
    {"id": 28, "difficulty": "medium", "question": "Solve by elimination: 2(x+1) = 3(y-1) and 5(x+2) = 2(y+3)", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 29, "difficulty": "medium", "question": "Solve by elimination: (x/2) + (y/3) = 2 and (x/3) + (y/2) = 13/6", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 1, y = 4", "D": "x = 4, y = 1"}, "correct_answer": "A"},
    {"id": 30, "difficulty": "medium", "question": "Solve by elimination: 4x - 3y = 5 and 3x + 4y = 6", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 0.33", "C": "x = 3, y = 2.33", "D": "x = 4, y = 3.67"}, "correct_answer": "A"},
    {"id": 31, "difficulty": "medium", "question": "Solve by elimination: 2x + 5y = 1 and 3x + 2y = 7", "options": {"A": "x = 3, y = -1", "B": "x = 2, y = -0.6", "C": "x = 1, y = -0.2", "D": "x = 4, y = -1.4"}, "correct_answer": "A"},
    {"id": 32, "difficulty": "medium", "question": "Solve by elimination: 6x + 7y = 19 and 8x - 5y = 17", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 1.86", "C": "x = 3, y = 0.14", "D": "x = 4, y = -0.71"}, "correct_answer": "A"},
    {"id": 33, "difficulty": "medium", "question": "Solve by elimination: 9x + 4y = 17 and 5x - 2y = 4", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = -0.25", "C": "x = 3, y = -2.5", "D": "x = 4, y = -4.75"}, "correct_answer": "A"},
    {"id": 34, "difficulty": "medium", "question": "Solve by elimination: 0.5x + 0.7y = 3.1 and 0.3x + 0.5y = 2.1", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 35, "difficulty": "medium", "question": "Solve by elimination: (x/4) + (y/5) = 1 and (x/2) - (y/3) = 1", "options": {"A": "x = 4, y = 5", "B": "x = 5, y = 4", "C": "x = 6, y = 3", "D": "x = 8, y = 0"}, "correct_answer": "A"},
    {"id": 36, "difficulty": "medium", "question": "Solve by elimination: 3(x-1) = 2(y+2) and 4(x+2) = 5(y-1)", "options": {"A": "x = 5, y = 7", "B": "x = 7, y = 5", "C": "x = 6, y = 6", "D": "x = 4, y = 8"}, "correct_answer": "A"},
    {"id": 37, "difficulty": "medium", "question": "Solve by elimination: 7x - 4y = 19 and 5x + 3y = 9", "options": {"A": "x = 3, y = 0.5", "B": "x = 2, y = -1", "C": "x = 4, y = 2.25", "D": "x = 1, y = -3"}, "correct_answer": "A"},
    {"id": 38, "difficulty": "medium", "question": "Solve by elimination: 8x + 3y = 11 and 3x + 4y = 10", "options": {"A": "x = 2/23, y = 79/23", "B": "x = 1, y = 1", "C": "x = 0.5, y = 2.125", "D": "x = 2, y = 1"}, "correct_answer": "A"},
    {"id": 39, "difficulty": "medium", "question": "Solve by elimination: 0.2x + 0.5y = 0.7 and 0.3x + 0.2y = 0.4", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = 0.6", "C": "x = 0.5, y = 1.2", "D": "x = 1.5, y = 0.8"}, "correct_answer": "A"},
    {"id": 40, "difficulty": "medium", "question": "Solve by elimination: (x/5) + (y/7) = 1 and (x/3) - (y/2) = -5", "options": {"A": "x = 15, y = 14", "B": "x = 10, y = 21", "C": "x = 5, y = 28", "D": "x = 20, y = 7"}, "correct_answer": "A"},
    {"id": 41, "difficulty": "hard", "question": "Solve by elimination: ax + by = a² + b² and bx + ay = 2ab", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = a-b, y = a+b"}, "correct_answer": "A"},
    {"id": 42, "difficulty": "hard", "question": "Solve by elimination: (a-b)x + (a+b)y = a² - 2ab - b² and (a+b)(x+y) = a² + b²", "options": {"A": "x = a+b, y = -(a+b)", "B": "x = a-b, y = a+b", "C": "x = a, y = -b", "D": "x = b, y = -a"}, "correct_answer": "A"},
    {"id": 43, "difficulty": "hard", "question": "Solve by elimination: (x/a) + (y/b) = 2 and ax - by = a² - b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = 2a, y = 2b", "D": "x = a², y = b²"}, "correct_answer": "A"},
    {"id": 44, "difficulty": "hard", "question": "Solve by elimination: x + y = a + b and ax - by = a² - b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = 2a, y = 2b"}, "correct_answer": "A"},
    {"id": 45, "difficulty": "hard", "question": "Solve by elimination: 2(ax - by) + (a + 4b) = 0 and 2(bx + ay) + (b - 4a) = 0", "options": {"A": "x = -1/2, y = 2", "B": "x = 2, y = -1/2", "C": "x = 1/2, y = -2", "D": "x = -2, y = 1/2"}, "correct_answer": "A"},
    {"id": 46, "difficulty": "hard", "question": "Solve by elimination: (a+b)x + (a-b)y = 2a² - 2b² and (a-b)x + (a+b)y = 2a² + 2b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = 2a, y = 2b"}, "correct_answer": "A"},
    {"id": 47, "difficulty": "hard", "question": "Solve by elimination: x + y = 2a and ax - by = a² - b²", "options": {"A": "x = a+b, y = a-b", "B": "x = a, y = a", "C": "x = a, y = b", "D": "x = b, y = a"}, "correct_answer": "A"},
    {"id": 48, "difficulty": "hard", "question": "Solve by elimination: (b/a)x + (a/b)y = a² + b² and x + y = 2ab", "options": {"A": "x = a², y = b²", "B": "x = ab, y = ab", "C": "x = a²b, y = ab²", "D": "x = 2a², y = 2b²"}, "correct_answer": "B"},
    {"id": 49, "difficulty": "hard", "question": "Solve by elimination: (x/a) - (y/b) = 0 and ax + by = a² + b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a², y = b²", "D": "x = 2a, y = 2b"}, "correct_answer": "A"},
    {"id": 50, "difficulty": "hard", "question": "Solve by elimination: a(x+y) + b(x-y) = a² - b² and b(x+y) + a(x-y) = a² + b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = a-b, y = a+b"}, "correct_answer": "A"},
    {"id": 51, "difficulty": "medium", "question": "Solve by elimination: 2x - 3y = 13 and 7x - 2y = 20", "options": {"A": "x = 2, y = -3", "B": "x = 1, y = -11/3", "C": "x = 3, y = -7/3", "D": "x = 4, y = -5/3"}, "correct_answer": "A"},
    {"id": 52, "difficulty": "medium", "question": "Solve by elimination: 3x + 4y = 25 and 5x - 6y = -9", "options": {"A": "x = 3, y = 4", "B": "x = 4, y = 3", "C": "x = 2, y = 4.75", "D": "x = 5, y = 2.5"}, "correct_answer": "A"},
    {"id": 53, "difficulty": "medium", "question": "Solve by elimination: 4x + 7y = 29 and 5x + 3y = 22", "options": {"A": "x = 3, y = 2.43", "B": "x = 2, y = 3", "C": "x = 4, y = 1.86", "D": "x = 1, y = 3.57"}, "correct_answer": "B"},
    {"id": 54, "difficulty": "medium", "question": "Solve by elimination: 6x - 5y = 16 and 3x + 7y = 5", "options": {"A": "x = 3, y = 0.4", "B": "x = 2, y = -0.57", "C": "x = 4, y = 1.6", "D": "x = 5, y = 2.8"}, "correct_answer": "A"},
    {"id": 55, "difficulty": "medium", "question": "Solve by elimination: 9x + 11y = 51 and 13x - 7y = 25", "options": {"A": "x = 4, y = 1.36", "B": "x = 3, y = 2.18", "C": "x = 2, y = 3", "D": "x = 5, y = 0.55"}, "correct_answer": "C"},
    {"id": 56, "difficulty": "medium", "question": "Solve by elimination: 0.3x + 0.4y = 1.7 and 0.7x - 0.2y = 0.8", "options": {"A": "x = 1, y = 3.5", "B": "x = 2, y = 2.75", "C": "x = 3, y = 2", "D": "x = 4, y = 1.25"}, "correct_answer": "C"},
    {"id": 57, "difficulty": "medium", "question": "Solve by elimination: (2x/3) + (y/2) = -1 and (x/3) - y = 3", "options": {"A": "x = -3, y = -2", "B": "x = -2, y = -3", "C": "x = -4, y = -1", "D": "x = -1, y = -4"}, "correct_answer": "A"},
    {"id": 58, "difficulty": "medium", "question": "Solve by elimination: (x+2)/4 = (y-1)/3 and (x-1)/2 = (y+2)/5", "options": {"A": "x = 6, y = 7", "B": "x = 7, y = 6", "C": "x = 8, y = 5", "D": "x = 5, y = 8"}, "correct_answer": "A"},
    {"id": 59, "difficulty": "medium", "question": "Solve by elimination: 3(x+2) = 2(y+3) and 4(x-1) = 3(y-1)", "options": {"A": "x = 4, y = 6", "B": "x = 6, y = 4", "C": "x = 5, y = 5", "D": "x = 3, y = 7"}, "correct_answer": "A"},
    {"id": 60, "difficulty": "medium", "question": "Solve by elimination: 5(x-1) + 3(y+2) = 10 and 2(x+3) - 4(y-1) = 8", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 2", "C": "x = 3, y = 0", "D": "x = 0, y = 3"}, "correct_answer": "A"},
    {"id": 61, "difficulty": "hard", "question": "Solve by elimination: (x+y)/(x-y) = 2 and (2x+3y)/(2x-3y) = 3", "options": {"A": "x = 5, y = 3", "B": "x = 3, y = 5", "C": "x = 4, y = 2", "D": "x = 6, y = 4"}, "correct_answer": "A"},
    {"id": 62, "difficulty": "hard", "question": "Solve by elimination: (3x+4y)/(3x-4y) = 5 and (5x+2y)/(5x-2y) = 7", "options": {"A": "x = 3, y = 2", "B": "x = 2, y = 3", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 63, "difficulty": "hard", "question": "Solve by elimination: (2x+3)/(y+2) = 5 and (3x+1)/(2y-1) = 4", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 64, "difficulty": "hard", "question": "Solve by elimination: (x+2y)/(2x+y) = 3/2 and (3x-y)/(x+3y) = 1/2", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = 1", "C": "x = 3, y = 1", "D": "x = 1, y = 3"}, "correct_answer": "A"},
    {"id": 65, "difficulty": "hard", "question": "Solve by elimination: a(x+y) + b(x-y) = a² - b² and b(x+y) + a(x-y) = a² + b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = a-b, y = a+b"}, "correct_answer": "A"},
    {"id": 66, "difficulty": "hard", "question": "Solve by elimination: (a+b)x + (a-b)y = 2a² - 2b² and (a-b)x + (a+b)y = 2a² + 2b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = 2a, y = 2b", "D": "x = a+b, y = a-b"}, "correct_answer": "A"},
    {"id": 67, "difficulty": "hard", "question": "Solve by elimination: (x/a) + (y/b) = a+b and (x/a²) + (y/b²) = 2", "options": {"A": "x = a², y = b²", "B": "x = a³, y = b³", "C": "x = a, y = b", "D": "x = ab, y = ab"}, "correct_answer": "A"},
    {"id": 68, "difficulty": "hard", "question": "Solve by elimination: (b+c)x + (c+a)y + (a+b)z = 0 and bcx + cay + abz = 0", "options": {"A": "x/(a(b-c)) = y/(b(c-a)) = z/(c(a-b))", "B": "x/(b-c) = y/(c-a) = z/(a-b)", "C": "x/a = y/b = z/c", "D": "x/(bc) = y/(ca) = z/(ab)"}, "correct_answer": "A"},
    {"id": 69, "difficulty": "hard", "question": "Solve by elimination: (x/a) + (y/b) = 1 and (x/b) + (y/a) = 1", "options": {"A": "x = ab/(a+b), y = ab/(a+b)", "B": "x = a, y = b", "C": "x = b, y = a", "D": "x = a+b, y = a-b"}, "correct_answer": "A"},
    {"id": 70, "difficulty": "hard", "question": "Solve by elimination: (x+y)/a = (x-y)/b = (x²+y²)/(a²+b²)", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a², y = b²", "D": "x = ab, y = ab"}, "correct_answer": "A"},
    {"id": 71, "difficulty": "medium", "question": "Solve by elimination: 7x - 4y = 19 and 5x + 3y = 9", "options": {"A": "x = 3, y = 0.5", "B": "x = 2, y = -1", "C": "x = 4, y = 2.25", "D": "x = 1, y = -3"}, "correct_answer": "A"},
    {"id": 72, "difficulty": "medium", "question": "Solve by elimination: 8x + 3y = 11 and 3x + 4y = 10", "options": {"A": "x = 2/23, y = 79/23", "B": "x = 1, y = 1", "C": "x = 0.5, y = 2.125", "D": "x = 2, y = 1"}, "correct_answer": "A"},
    {"id": 73, "difficulty": "medium", "question": "Solve by elimination: 0.2x + 0.5y = 0.7 and 0.3x + 0.2y = 0.4", "options": {"A": "x = 1, y = 1", "B": "x = 2, y = 0.6", "C": "x = 0.5, y = 1.2", "D": "x = 1.5, y = 0.8"}, "correct_answer": "A"},
    {"id": 74, "difficulty": "medium", "question": "Solve by elimination: (x/5) + (y/7) = 1 and (x/3) - (y/2) = -5", "options": {"A": "x = 15, y = 14", "B": "x = 10, y = 21", "C": "x = 5, y = 28", "D": "x = 20, y = 7"}, "correct_answer": "A"},
    {"id": 75, "difficulty": "medium", "question": "Solve by elimination: 3(x-2) = 2(y-1) and 4(x+1) = 5(y+2)", "options": {"A": "x = 8, y = 10", "B": "x = 10, y = 8", "C": "x = 12, y = 6", "D": "x = 6, y = 12"}, "correct_answer": "A"},
    {"id": 76, "difficulty": "medium", "question": "Solve by elimination: (2x+1)/3 = (y+2)/4 and (3x-2)/2 = (2y+1)/5", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 77, "difficulty": "medium", "question": "Solve by elimination: 5x - 6y = 1 and 3x + 4y = 17", "options": {"A": "x = 5, y = 4", "B": "x = 4, y = 5", "C": "x = 3, y = 6", "D": "x = 6, y = 3"}, "correct_answer": "A"},
    {"id": 78, "difficulty": "medium", "question": "Solve by elimination: 2x + 5y = 12 and 3x - 4y = 1", "options": {"A": "x = 2, y = 1.6", "B": "x = 3, y = 1.2", "C": "x = 4, y = 0.8", "D": "x = 1, y = 2"}, "correct_answer": "A"},
    {"id": 79, "difficulty": "medium", "question": "Solve by elimination: 0.4x + 0.3y = 1.7 and 0.7x - 0.2y = 0.8", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 1, y = 4.33", "D": "x = 4, y = 0.33"}, "correct_answer": "A"},
    {"id": 80, "difficulty": "medium", "question": "Solve by elimination: (x+3)/4 = (2y-1)/5 and (x-1)/3 = (y+2)/2", "options": {"A": "x = 5, y = 6", "B": "x = 6, y = 5", "C": "x = 7, y = 4", "D": "x = 4, y = 7"}, "correct_answer": "A"},
    {"id": 81, "difficulty": "hard", "question": "Solve by elimination: (3x-2)/(2y-3) = 4 and (4x+1)/(3y+2) = 5", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 4, y = 1", "D": "x = 1, y = 4"}, "correct_answer": "A"},
    {"id": 82, "difficulty": "hard", "question": "Solve by elimination: (2x+3y)/(3x+2y) = 13/12 and (3x+4y)/(4x+3y) = 5/6", "options": {"A": "x = 2, y = 3", "B": "x = 3, y = 2", "C": "x = 1, y = 4", "D": "x = 4, y = 1"}, "correct_answer": "A"},
    {"id": 83, "difficulty": "hard", "question": "Solve by elimination: (x+2y)/(2x+y) = 2 and (2x+3y)/(3x+2y) = 3/2", "options": {"A": "x = 1, y = 2", "B": "x = 2, y = 1", "C": "x = 3, y = 1", "D": "x = 1, y = 3"}, "correct_answer": "A"},
    {"id": 84, "difficulty": "hard", "question": "Solve by elimination: a(x+y) - b(x-y) = a² - b² and b(x+y) + a(x-y) = a² + b²", "options": {"A": "x = a, y = b", "B": "x = b, y = a", "C": "x = a+b, y = a-b", "D": "x = a-b, y = a+b"}, "correct_answer": "A"},
    {"id": 85, "difficulty": "hard", "question": "Solve by elimination: (x/a²) + (y/b²) = 1 and (x/a) + (y/b) = a+b", "options": {"A": "x = a³, y = b³", "B": "x = a²b, y = ab²", "C": "x = a², y = b²", "D": "x = a, y = b"}, "correct_answer": "A"},
    {"id": 86, "difficulty": "hard", "question": "Solve by elimination: (b-c)x + (c-a)y + (a-b)z = 0 and bcx + cay + abz = 0", "options": {"A": "x/(a(b-c)) = y/(b(c-a)) = z/(c(a-b))", "B": "x/(b-c) = y/(c-a) = z/(a-b)", "C": "x/a = y/b = z/c", "D": "x/(a²) = y/(b²) = z/(c²)"}, "correct_answer": "A"},
    {"id": 87, "difficulty": "hard", "question": "Solve by elimination: (x+y)/a = (y+z)/b = (z+x)/c", "options": {"A": "x/(b+c-a) = y/(c+a-b) = z/(a+b-c)", "B": "x/a = y/b = z/c", "C": "x/(a+b) = y/(b+c) = z/(c+a)", "D": "x/(b-c) = y/(c-a) = z/(a-b)"}, "correct_answer": "A"},
    {"id": 88, "difficulty": "hard", "question": "Solve by elimination: (x/a) + (y/b) = 2 and ax - by = a² - b², then find x² + y²", "options": {"A": "a² + b²", "B": "2(a² + b²)", "C": "(a² + b²)²", "D": "a²b²"}, "correct_answer": "A"},
    {"id": 89, "difficulty": "hard", "question": "Solve by elimination: (x+y)/(a+b) = (x-y)/(a-b) and x² + y² = 2a², then find xy", "options": {"A": "a²", "B": "2a²", "C": "a²/2", "D": "0"}, "correct_answer": "D"},
    {"id": 90, "difficulty": "hard", "question": "Solve by elimination: 2x + 3y = 7 and 6x + 9y = 21, then what is the relationship between x and y?", "options": {"A": "y = (7-2x)/3", "B": "x = (7-3y)/2", "C": "3x + 2y = 7", "D": "Both A and B"}, "correct_answer": "D"},
    {"id": 91, "difficulty": "medium", "question": "Solve by elimination: 4x + 9y = 30 and 7x - 5y = 16", "options": {"A": "x = 3, y = 2", "B": "x = 2, y = 2.44", "C": "x = 4, y = 1.56", "D": "x = 5, y = 1.11"}, "correct_answer": "A"},
    {"id": 92, "difficulty": "medium", "question": "Solve by elimination: 0.6x + 0.8y = 2.8 and 0.3x - 0.4y = -0.2", "options": {"A": "x = 2, y = 2", "B": "x = 3, y = 1.25", "C": "x = 4, y = 0.5", "D": "x = 1, y = 2.75"}, "correct_answer": "A"},
    {"id": 93, "difficulty": "medium", "question": "Solve by elimination: (x/4) + (y/5) = 2 and (x/2) - (y/3) = 1", "options": {"A": "x = 8, y = 10", "B": "x = 10, y = 8", "C": "x = 12, y = 5", "D": "x = 6, y = 12.5"}, "correct_answer": "A"},
    {"id": 94, "difficulty": "medium", "question": "Solve by elimination: 3(x+1) = 2(y+2) and 5(x-1) = 3(y-1)", "options": {"A": "x = 5, y = 7", "B": "x = 7, y = 5", "C": "x = 6, y = 6", "D": "x = 4, y = 8"}, "correct_answer": "A"},
    {"id": 95, "difficulty": "medium", "question": "Solve by elimination: (3x-1)/2 = (2y+3)/5 and (x+2)/3 = (y-1)/4", "options": {"A": "x = 4, y = 5", "B": "x = 5, y = 4", "C": "x = 6, y = 3", "D": "x = 3, y = 6"}, "correct_answer": "A"},
    {"id": 96, "difficulty": "medium", "question": "Solve by elimination: 6x - 7y = 5 and 8x + 9y = 25", "options": {"A": "x = 2, y = 1", "B": "x = 1, y = 0.14", "C": "x = 3, y = 1.86", "D": "x = 4, y = 2.71"}, "correct_answer": "A"},
    {"id": 97, "difficulty": "medium", "question": "Solve by elimination: 0.5x + 0.6y = 2.3 and 0.3x + 0.2y = 1.1", "options": {"A": "x = 2, y = 2.17", "B": "x = 3, y = 1.33", "C": "x = 1, y = 3", "D": "x = 4, y = 0.5"}, "correct_answer": "A"},
    {"id": 98, "difficulty": "medium", "question": "Solve by elimination: (x+2)/5 = (y-3)/4 and (x-1)/3 = (y+2)/2", "options": {"A": "x = 13, y = 15", "B": "x = 15, y = 13", "C": "x = 12, y = 14", "D": "x = 14, y = 12"}, "correct_answer": "A"},
    {"id": 99, "difficulty": "medium", "question": "Solve by elimination: 9x + 10y = 29 and 11x - 8y = 17", "options": {"A": "x = 3, y = 0.2", "B": "x = 2, y = 1.1", "C": "x = 1, y = 2", "D": "x = 4, y = -0.7"}, "correct_answer": "A"},
    {"id": 100, "difficulty": "medium", "question": "Solve by elimination: (2x/5) + (3y/4) = 2 and (x/3) - (y/2) = -1", "options": {"A": "x = 3, y = 4", "B": "x = 4, y = 3", "C": "x = 2, y = 5", "D": "x = 5, y = 2"}, "correct_answer": "A"}
  ]
}