Problem #PRU-100604

Problem

a) Two numbers, $a$ and $b$, are relatively prime and their product is equal to $3^5\times 7^2$. What could these numbers be? Find all the possibilities.

b) The gcd of two numbers, $c$ and $d$, is $20$ and their product is $2^4\times 5^3$. What could these numbers be? Find all the answers.