Agrocer wants to make a 10-pound mixture of cashews and peanuts that he can sell for $3.29 per pound.
if cashews cost $5.60 per pound and peanuts cost $2.30 per pound, how many pounds of each must he mix?

If you would like to know how many pounds of cashews and peanuts must a grocer mix, you can calculate this using the following steps: 

cashews ... x pounds = ? ... $5.60 per pound
peanuts ... y pounds = ? ... $2.30 per pound

x + y = 10 pounds ... x = 10 - y

x * $5.60 + y * $2.30 = 10 * $3.29
x * 5.60 + y * 2.30 = 32.90
(10 - y) * 5.60 + y * 2.30 = 32.90
56 - y * 5.60 + y * 2.30 = 32.90
56 - 32.90 = 5.60 * y - 2.30 * y
23.10 = 3.30 * y
y = 23.10 / 3.30
y = 7 pounds

x = 10 - y = 10 - 7 = 3 pounds

The correct result would be 3 pounds of cashews and 7 pounds of peanuts.