SSC CGL 2024 PYQ — Question 73

SSC CGL - 24 Sep 2024 - Shift 2 • Quantitative Aptitude • Q73

For what value of K does the following system have an infinite number of solutions?

x + 2Ky - 8 = 0

2x - y - 16 = 0

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. -1/4

x + 2Ky - 8 = 0

⇒ x + 2Ky = 8   .....(1)

2x - y - 16 = 0

⇒ 2x - y = 16   .....(2)

If a1x + b1y = c1 and a2x + b2y = c2 then (a1/a2) = (b1/b2) = (c1/c2) [Infinite solutions]

Here, a1 = 1, b1 = 2K, c1 = 8 and a2 = 2, b2 = -1, c2 = 16

So, 1/2 = (2K)/(-1) = 8/16

Then, 1/2 = (2K)/(-1)

K = -1/4

Let's verify if this value of K satisfies the third ratio,

(2K)/(-1) = 8/16

(-1/2)/(-1) = 1/2

1/2 = 1/2

Therefore, the value of K for which the system has an infinite number of solutions is -1/4.