Question

Mia is three years older than twice her sister Brooke’s age. The sum of their ages is less than 30. What is the greatest age Brooke could be?

Answer 1

answers could be
7
8
9
10

Answer 2

m = 2b + 3
m + b < 30
so lets sub 2b + 3 in for m in the inequality

2b + 3 + b < 30
3b + 3 < 30
3b < 30 - 3
3b < 27
b < 9

if it is less then 9, it has to be 8.