HCF and LCM

The HCF of two numbers is 1/6th of the LCM of those two numbers. if one of the numbers is 15, find the other?

let HCF = H
therefore LCM = 6H
so, 6 is the product of the uncommon factors
the uncommon factors would be 2 and 3.
since one number is 15, it must have 3 as the uncommon factors.
so, HCF = 15/3 = 5
so, the other number is = 5 x 2 = 10