What is the solution of the pair of linear equations 37x + 43y = 123, 43x + 37y = 117?
(a) x = 2, y = 1 (b) x = −1, y = 2
(c) x = −2, y = 1 (d) x = 1, y = 2
CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ]
CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ]
Last updated at August 14, 2026 by Teachoo
Transcript
Question 40 What is the solution of the pair of linear equations 37x + 43y = 123, 43x + 37y = 117? (a) x = 2, y = 1 (b) x = ā1, y = 2 (c) x = ā2, y = 1 (d) x = 1, y = 2 Given equations 37š„ + 43š¦ = 123 ā¦(1) 43š„ + 37š¦ = 117 ā¦(2) Adding both equations (1) and (2) (37š + 43š) + (43š + 37š) = 123 + 117 (37š„ + 43š„) + (43š¦ + 37š¦) = 240 80š„ + 80š¦ = 240 80(š + š) = 240 š„ + š¦ = 240/80 š„ + š¦ = 3 Now, subtracting (1) and (2) (37š + 43š) ā (43š + 37š) = 123 ā 117 (37š„ ā 43š„) + (43š¦ ā 37š¦) = 8 ā8š„ + 8š¦ = 8 8(āš + š) = 8 āš„ + š¦ = 8/8 āš„ + š¦ = 1 Adding (3) and (4) (š„ + š¦) + (āš„ + š¦) = 3 + 1 2y = 4 y = 4/2 y = 2 Putting y = 2 in (3) š„ + š¦ = 3 š„ + 2 = 3 š„ = 3 ā 2 š„ = 1 ā“ x = 1, y = 2 So, the correct answer is (d)