What does the delicatessen charge for a turkey sandwich? What is the charge for an order of french fries?

Question

he employees of a hardware store ordered lunch from a local delicatessen. The lunch consisted of 4 turkey sandwiches and 7 orders of french fries, for a total cost of $18.90. The next day, the employees ordered 5 turkey sandwiches and 5 orders of french fries totaling $21.00. What does the delicatessen charge for a turkey sandwich? What is the charge for an order of french fries?

Answer 1

Let x = the price of a turkey sandwich and y = the price of french fries.

4x+7y=18.90

5x+5y=21.00

y = (21-5x)/5

4x + 7(21-5x)/5 = 18.90

Multiply through by 5

20x +147-35x=94.50

15x=52.5

x=52.5/15 = 3.50

y = (21-17.5)/5 = 0.70

Turkey Sandwich = $3.50

French Fries = $0.70