Question

Gordon rolls a fair dice 162 times.

How many times would Gordon expect to roll a number greater than 3?

Answer 1

81 times.

Explanation:

A dice has 6 sides.

The dice is fair, so each side has a 1/6 chance of being rolled.

The are 3 numbers greater than 3 - 4, 5 and 6.

Each of those numbers have a 1/6 chance of being rolled.

Together, their chance of being rolled is:

1/6 + 1/6 + 1/6 = 3/6 = 1/2

The dice is rolled 162 times.

162 x 1/2 = 81

Gordon should roll a number greater than 3 81 times.