If x was the amount of money Mr. Green had remaining, and y was the amount of money Mrs. Green had remaining, then:
x / y = 3 / 2
And, since they spent the same amount of money:
200 - x = 180 - y
We can solve this system of equations through substitution.
x = 3/2 y
200 - 3/2 y = 180 - y
20 = 1/2 y
y = 40
So Mrs. Green had $40 remaining. Since she started with $180, she must have spent $140. So that was the cost of the shirt. Let's check our answer by seeing how much Mr. Green had remaining and how it compares.
