For this case, the first thing we must do is define variables.
We have then:
x: Maggie's age
y: Age of Maggie's brother
We write the system of equations that models the problem.
We have then:

We solve the system of equations.
For this, we use substitution:

From here, we clear the value of x:


Answer:
Maggie is 9 years old
18 t - 18 t * 30% = 18 t - 17 * 0,3 = 18 t - 5,4 t = 12,6 t
In percentage form it is 83.33% repeating, but in dollars it is $50
The answer to the question is the second story problem
7____ is the one that couldn't used to complete a table of eqiuvalent ratios