Last week, Doug bought 7 pizzas and 7 cakes for a total of $91. Today, Doug bought 24 pizzas and 20 cakes for a total of $292. What is the cost of a pizza in dollars.

Question

Neither item has changed in price.

Answer 1

Two independent equations, 2 unknowns we can solve for price of pizza.

Let P = Price of pizza

Let C = Price of cake

Equation 1: 7P + 7C = 91

Equation 2: 24P + 20C = 292

Equation 1: (divide by 7)

P + C = 13

Multiply equation 2 by -20 ( to eliminate C )

Equation 1: 24P + 20C = 292

Equation 2 multiplied by -20: -20P - 20C = -260

Add the two equations:

4P + 0C = 32

P = 8 ( price of Pizza )