Let the present ages of the younger sister be ‘a’.
Given, girl is twice as old as her sister.
Age of elder sister = 2a
Also, four years ago, the product of their...
If two numbers are relatively prime then their greatest common factor will be 1.
∴ HCF (a,b) = 1
Using the formula, Product of two numbers = HCF × LCM
we conclude that,
a...