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

lets say Mia is represented by M and Brook is represented by B.

M=3xB
M+B=30

then you can plug it in to solve for B if M=3xB you can replace M in the bottom question with that

3B+B=30

4B=30
divide both by 4 to solve for B

B=7.5

Plug in your answer to check to be sure both sides are equal

3x7.5+7.5=30

30=30

So brook is 7 and 1/2

Mia is 3xB

7.5x3=30

Answer 2

Answer: The greatest age Brooke could be is 8

Explanation:

Hi, to answer this question we have to write an equation and an inequality with the information given:

M = 2B+3 ⇒Mia is three years older than twice her sister Brooke’s age.

M +B < 30 ⇒the sum of their ages is less than 30.

Replacing M in the inequality

2B+3+B <30

2B+B <30-3

3B<27

B <27/3

B< 9

The greatest age Brooke could be is 8. (Not nine because the expression isn't less or equal B≤9)

Feel free to ask for more if needed or if you did not understand something.