In a department store there were a certain number of red tshirts, blue tshirts, and yellow tshirts. 3/7 of the tshirts were red, 1/3 of them were blue, and the rest were yellow. If there were 20 more red tshirts than bake tshirts, how many yellow tshirts were there?

Answer 1

If there were x shirts,
r = 3/7 x
b = 1/3 x
r = b + 20

3/7 x = 1/3 x + 20
x = 210

So, now figure the red and "bake", and the rest are yellow.