Math
posted by Samantha on .
There are 40 tags numbered one through 40 in a bag. What is the propability that Glen will randomly pick a multiple of 5 and then a multiple of 9 without replacing the first tag?

Multiples of 5 = 5, 10, 15, 20, 25, 30, 35, 40 = 8/40
After picking the 5, there are only 39 tags for the second draw = 9, 18, 27, 36 = 4/39
Probability of all/both events occurring is found by multiplying probabilities of the individual events.
8/40 * 4/39 = ? 
5/195

4/195 is the answer