Ienter 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
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.