#### Answer

15

#### Work Step by Step

Multiples of 5: 5, 10, 15, 20, 25
In order to find the LCM of 3 and 5, we must find the first multiple of 5 that is also divisible by 3.
5 and 10 are not divisible by 3.
$15\div3=5$
Therefore, 15 is the LCM of 3 and 5.