Question

Peter had 400 stamps. 5/8 of them are U.S. stamps and the rest are Canadian stamps. He gave 1/5 of the U.S. stamps to his friend. How many stamps did he have left?

Answer 1

You can set this up as a system of equations as follows. U=U.S. Stamps,

C=Canadian Stamps, P=Peter's Stamps

400*5/8=U

U+C=400

1/5*U = P

U is easy to solve for. If we multiply we get

U=250

Then we can solve for C although we don't really need to know C but we can find it anyway

C=400-250

C=150

Then we can also solve for P

1/5*250=p

p=50

If he gave 50 stamps to peter then he has

400-50 stamps left or 350