# 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?

Jan 11, 2017

Preetha's age is $7$ years.

#### Explanation:

We consider Preetha's age as $x$, since it is an unknown figure.

From the given data, we know Davindra's age and also how it compares to Preetha's age. Hence, we can write:

$2 x + 1 = 15$

Subtract $1$ from each side.

$2 x = 14$

Divide both sides by $2$.

$x = 7$