UPSC NDA Math Model Paper 3

Here, 2x + y = 6 ... (1)
And, 3y = 8 + 4x
⇒4x - 3y = -8 .... (2)
Multiply (1) and subtract from (2), we get
(4x + 2y = 12) - (4x - 3y = -8 )
⇒ 5y = 20
⇒ y = 4
Putting y = 4 in (1), we get
x = 1
Now let's check which equation in the option satisfy the values of x and y
1. x + y = 1 + 4 = 5
Hence, option (1) is correct.