CAT 1991 — QA Question 12

For two lines a₁x + b₁y = c₁ and a₂x + b₂y = c₂ to be parallel, the condition is

$\frac{a_1}{a_2}$ = $\frac{b_1}{b_2}$ ≠ $\frac{c_1}{c_2}$

For no solution, lines must be parallel and not over lapping

⇒ $\frac{2}{k}=\frac{-8}{4}\ne \frac{3}{10}$

∴ k = − 1.

Hence, option (c).