Question

Find the probability of rolling a 5 or 6 on a fair dice

Answer 1

`(1)/(3)`

Explanation:

`(1)/(6)` +
`(1)/(6)`

This is because there is only one "5" and one "6" in a dice. Moreover the total number of numbers in a dice are 6 so the denominator will be 6. Then when the word 'or' is present it means that both the probabilities must be added.

P (of rolling a 5 or 6 on a fair dice) =
`(1)/(6)` +
`(1)/(6)`

`(2)/(6)` can be simplified further. Both 2 and 6 are factors of 2 so..

`(2)/(6)` =
`(1)/(3)`

P (of rolling a 5 or 6 on a fair dice) =
`(1)/(3)`