Question

A store is having a sale on chocolate chips and walnuts. For 7 pounds of chocolate chips and 9 pounds of walnuts, the total cost is $53. For 5 pounds of chocolate chips and 3 pounds of walnuts, the total cost is $25. Find the cost for each pound of chocolate chips and each pound of walnuts.

Answer 1

Answer:

1 lb chocolate chips = $2.75

1 lb walnuts = $3.75

Step-by-step explanation:

Write equations.

7x + 9y = 53

5x + 3y = 25

Multiply 2nd equation by 3 and then subtract.

7x + 9y = 53

-(15x + 9y = 75)

-8x = -22

x = 11/4 = 2.75

Substitute this x value into an equation.

7x + 9y = 53

7(2.75) + 9y = 53

9y = 33.75

y = 3.75