Question

A grocer has two kinds of candies: one sells for 90 cents per pound and the other sells for 40 cents per pound. How many pounds of each kind must he use to make 100 pounds he can sell for 85 cents per pound?

Answer 1

The grocer must use
 .. 90 lbs of 90-cent candy
 .. 10 lbs of 40-cent candy.

I find these X diagrams useful for solving mixture problems.