SSC CHSL 2024 PYQ — Question 74

The correct answer is option 1 i.e. 4. 

For two lines with equations,

a₁x + b₁y + c₁ = 0 and a₂x + b₂y + c₂ = 0

These lines are parallel if a₁/a₂ = b₁/b₂ ≠ c₁/c₂.

According to the given question,

Two equations are 5x + ky − 2 = 0 and (k + 1)x + 4y + 7 = 0,

Now, ${5 \over (k + 1)} = {k \over 4}$

⇒ k² + k - 20 = 0

⇒ k² + 5k - 4k - 20 = 0

⇒ k(k + 5) - 4(k + 5) = 0

⇒ (k + 5)(k - 4) = 0

⇒ k = -5; k = 4 (k >0)