Answer
180
Work Step by Step
15 , 9, 20
Use prime factorization to find the least common multiple of 15 , 9 and 20
Find the prime factorization for each number
15 = 3 * 5
9 = 3 * 3
20 = 2 * 2 * 5
3 and 5 occur most often in the factorization of 15
3 occur most often in the factorization of 9
2 * 2 occur most often in the factorization of 20
L.C.M. = 3 * 5 *3 *2 *2 = 180