Question

Thirty cards are numbered from 1 to 30, inclusive. If one card is drawn at random, what is the probability that the number on the card will be divisible by either 3 or 5?

Answer 1

Find the numbers between 1 and 30 that are divisible by 3 or 5:

Divisible by 3:

3, 6, 9, 12, 15, 18, 21, 24, 27, 30

Divisible by 5:

5, 10, 15, 20, 25, 30

There are 10 numbers divisible by 3 and 6 numbers divisible by 5 for a total of 16 numbers.

The probability is 16/30, which reduces to 8/15 are divisible by 3 or 5.