Question

A die is rolled. What is the probability of the outcome is either 2 or a number less than 4?

Answer 1

P(2)`=1/6`

P(`<4`)`=1/2`

Explanation:

As 2 is also a number less than 4, I will assume that they are two separate questions below.

We have to know that for a fair dice, there is an equal probability of getting any of the six numbers: 1, 2, 3, 4, 5, 6.
Hence, the probability of getting a certain number is `1/6`.

For getting a 2,
The total number of possible outcomes `=6`
The number of favourable outcomes (i.e. outcomes that fulfills the requirement) `=1`

Therefore, P(`2`)`=1/6`.

For getting a number less than 4,
The total number of possible outcomes `=6`
The number of favourable outcomes (i.e. outcomes that fulfills the requirement)
`=3` (remember that 4 is not counted)

Therefore, P(`<4`)`=3/6=1/2`.

Note: we use P() to refer to probability, with the words inside the bracket giving a brief description of the probability we are talking about.