Question

Sarah is twice as old as her younger brother. The sum of twice her age and three times her brother's age is

35. Write and solve a system of equations to do to determine how old Sarah is and how old her brother is.

Answer 1

Answer: Her brother is 5 years old.

Explanation:

s = 2b

4b + 3b = 35

7b = 35

First, I used s to represent Sarah's age. We are told that she is twice her brother, I used b to represent her brother's age. The sum of twice her age is 4 times her brother's age (2b + 2b) and 3 times her brother's age is 3b.