Question

The probability of guessing the correct answer of a certain test question is `x/12`. If the probability of not guessing the correct answer is `5/6` then find the value of x.

Answer 1

Given:

Probability of guessing a correct answer to a certain question is `x/12`

Probability of not guessing a correct answer to the same question `5/6`

To find:

The value of x = ?

Calculation:

`x/12 + 5/6 = 1`     ...(∵ sum of the probabilities of an even and its complement is) always 1)

`x/12 + 10/12 = 1`

`(x+10)/12 = 1`

x + 10 = 12

x = 12 − 10

x = 2