Question

The probability of guessing the correct answer to a certain question is $\frac{x}{3}$. If the probability of not guessing the correct answer is $\frac{x}{3}$, then find $x$.

• A. $\frac{2}{3}$
• B. $\frac{3}{2}$
• C. $1$
• D. $0.5$

Answer 1

The correct option is B $\frac{3}{2}$

Let P(A) be the probability of guessing the correct answer and P(B) be the probability of not guessing the correct answer.

We know that the sum of probabilities of all possible outcomes of an event is 1.

So, P(A) + P(B) = 1

$\Rightarrow \frac{x}{3}+\frac{x}{3}=1$

$\Rightarrow \frac{2x}{3}=1$

$\Rightarrow x=\frac{3}{2}$