The greatest common divisor of positive integers m and n is 8. The least common multiple of m and n is 120. What is the least possible value of m+n?

8 = 2^3

120 = 2^3 * 3 * 5

m=2^3 x 3 ==24

n ==2^3 x 5 ==40

m+n ==24 + 40 ==64