Question

solve using a system of equations: ellen wishes to mix candy worth $1.70 per pound with candy worth $2.50 per pound to form 40 pounds of candy worth $2 per pound. How many pounds of the more expensive candy should she use?

Answer 1

15 pounds

Explanation:

let 'x' = $1.70 candy

let 'y' = $2.50 candy

System:

x + y = 40

1.7x + 2.5y = 40(2)

let 'x' = '40-y'

now substitute '40-y' for 'x' to get:

1.7(40-y) + 2.5y = 80

68 - 1.7y + 2.5y = 80

-1.7y + 2.5y = 12

0.8y = 12

y = 12/0.8

y = 15

check:

1.7(25) + 15(2.5) should equal 80

80 = 80