The product of two-digit numbers is 2160 and their G.C.M is 12. The numbers are?

Let the number be 12a and 12b
Then 12a x 12b = 2160
or ab = 15
∴ Values of co-primes a and b are (1, 15), (3, 5)
So, the two digit number are 12 x 3 and 12 x 5 i.e. 36 and 60 .