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 `x/5`, then find the value of x.

Answer 1

Probability of guessing the correct answer = `x/3`

P(E) = `x/3`

Probability of not guessing the correct answer = `x/5`

P(E)’ = `x/5`

But P(E) + P(E)’ = 1

`x/3 + x/5` = 1

`(5x + 3x)/5` = 1

⇒ `(8x)/15` = 1

8x = 15

x = `15/8`

∴ The value of x = `15/8`