The LCM of two numbers is 20 times their HCF. The sum of the HCF and LCM is 2520. If one of the numbers is 480 the other number is:

600

LCM = 20 × HCF (given)

Let HCF = x

LCM = 20x (according to the question)

LCM + HCF = 2520

20x + x = 2520

21x = 2520

x = 120

The HCF is 120

The LCM is 2400

One number is 480

Other number is y

The product if the two number is = HCF × LCM

480 × y = 120 × 2400

y = 600