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

Ques 40 (MCQ) - What is the solution of the pair of linear equations - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ]

part 2 - Question 40 - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ] - Solutions of Sample Papers for Class 10 Boards - Class 10
part 3 - Question 40 - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ] - Solutions of Sample Papers for Class 10 Boards - Class 10

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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 = āˆ’1, y = 2 (c) x = āˆ’2, y = 1 (d) x = 1, y = 2 Given equations 37š‘„ + 43š‘¦ = 123 …(1) 43š‘„ + 37š‘¦ = 117 …(2) Adding both equations (1) and (2) (37š’™ + 43š’š) + (43š’™ + 37š’š) = 123 + 117 (37š‘„ + 43š‘„) + (43š‘¦ + 37š‘¦) = 240 80š‘„ + 80š‘¦ = 240 80(š’™ + š’š) = 240 š‘„ + š‘¦ = 240/80 š‘„ + š‘¦ = 3 Now, subtracting (1) and (2) (37š’™ + 43š’š) āˆ’ (43š’™ + 37š’š) = 123 āˆ’ 117 (37š‘„ āˆ’ 43š‘„) + (43š‘¦ āˆ’ 37š‘¦) = 8 āˆ’8š‘„ + 8š‘¦ = 8 8(āˆ’š’™ + š’š) = 8 āˆ’š‘„ + š‘¦ = 8/8 āˆ’š‘„ + š‘¦ = 1 Adding (3) and (4) (š‘„ + š‘¦) + (āˆ’š‘„ + š‘¦) = 3 + 1 2y = 4 y = 4/2 y = 2 Putting y = 2 in (3) š‘„ + š‘¦ = 3 š‘„ + 2 = 3 š‘„ = 3 āˆ’ 2 š‘„ = 1 ∓ x = 1, y = 2 So, the correct answer is (d)

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