If two positive integers p and q can be expressed as p = ab2 and q = a3 b; where a, b being prime numbers, them LCM (p, q) is equal to
Let p = ab2 = a × b × b
And q = a3b = a × a × a × b
⇒ LCM of p and q = LCM (ab2, a3b) = a × b × b × a × a = a3b2
[Since, LCM is the product of the greatest power of each prime factor involved in the number]