The ratio of two numbers is 7 : 13 and their HCF is 8. Their LCM is:

Let the numbers be 7x and 13x.

Then, H.C.F. = x = 8

First number is,

⇒ 7x = 7 × 8 = 56

Second number is,

⇒ 13x = 13 × 8 = 104

a × b = HCF × LCM

⇒ 56 × 104 = 8 × LCM

⇒ LCM = 728