Answer
$45$
Work Step by Step
The least common multiple ($LCM$) of two numbers $a$ and $b$ is the smallest number which is a multiple of both numbers $a$ and $b$..
We have to determine the $LCM$ of the numbers $9$ and $15$.
First we write the prime factorization of each number:
$9=3\cdot 3$
$15=3\cdot 5$
Then we take each factor the greatest number of times that it appears in any one prime factorization:
$LCM=3\cdot 3\cdot 5 = 45$.
The $LCM$ of the given numbers is $45$.
