Question

the probability of guessing the correct answer to a certain question is x/3. if the probability of not guessing the correct answer is 5x/3 then find the value of x

Answer 1

as they are complementary events

sum of the probabilities will be equal to 1

so x=1/2

Answer 2

we know that the sum of the probability = 1



$\frac{x}{3} + \frac{5x}{3} = 1 \\ \frac{x+5x}{3} = 1 \\ \frac{6x}{3} = 1$

6x = 3

x = 3/6 = 1/2