Davindra, who is 15 years old, is one year older than twice the age of her younger sister, Preetha. How do you find the age of Preetha and justify each step?
Preetha's age is
We consider Preetha's age as
From the given data, we know Davindra's age and also how it compares to Preetha's age. Hence, we can write:
Divide both sides by