Suppose you want to fill nine 1-lb tins with a snack mix. You have 15 and plan to buy almonds for 2.45 per lb, hazelnuts for 1.85 per lb, and raisins for .80 per lb. You want the mix to contain an equal amount of almonds and hazelnuts and twice as much of the nuts as the raisins by weight.
x + y + z = 9 2.45x + 1.85y + 0.8z = 15 x+y = 2z.

a. Explain how each equation to the right relates to the problem. What does each variable represent?