I enter the mall with $75 dollars. I spend a dollars at American Eagle, which is 4 more than the amount I spent at Banana Republic. I also spent 15 less at American Eagle than I spent at Cole Haan. How much money do I have left after shopping at these three stores?

I spent a dollars at American Eagle, which is 4 more than the amount I spent at Banana Republic (b).

a = b + 4. Therefore: b = a - 4

Also I spent 15 less at American Eagle than I spent in Cole Haan (c).

a = c - 15, or: c = a + 15.

75 - a - (a - 4) - (a + 15) = 75 - a - a + 4 - a - 15 =

= 64 - 3 a

Answer: I have 64 - 3a dollars left after shopping at these three stores. Now we just have to know how much dollars I spent at American Eagle and we will have the amount in dollars.