If you would like to know how many pounds of each kind of candy must the grocer use to make 100 pounds worth 85 cents a pound, you can calculate this using the following steps:
Candy number 1:
c pounds = ? ... 90 cents a pound
Candy number 2:
d pounds = ? ... 40 cents a pound
c + d = 100 pounds
c = 100 pounds - d
c 90 cents + d 40 cents = 100 pounds 85 cents
(100 - d) 90 + d 40 = 100 85
100 90 - 90 d + d 40 = 100 85
100 90 - 100 85 = 90 d - 40 d
500 = 50 d
d = 500 / 50
d = 10 pounds
c = 100 pounds - d = 100 - 10 = 90 pounds
There should be 90 pounds of candy number 1 and 10 pounds of candy number 2.
90 pounds 90 cents + 10 pounds * 40 cents = 8500 cents per 100 pounds
8500 cents / 100 pounds = 85 cents a pound
