Question

The probability of guessing the correct answer to certain test questions is $\frac{y}{4}$. If the probability of not guessing the correct answer to these questions is $\frac{3}{4}$, then the value of y is:

• A. $\frac{1}{2}$
• B. $\frac{1}{4}$
• C. 1
• D. 0

Answer 1

The correct option is C 1

Given, P(correct answer) = $\frac{y}{4}$ and P(incorrect answer) = $\frac{3}{4}$.

P(correct answer) = 1 - P(incorrect answer) [$\because$ P(A)+P($\overline{A}$) = 1]

$\frac{y}{4}$ = 1 - $\frac{3}{4}$

$⟹$ y = 1