Question

A corner store sells two kinds of baked goods: cakes and pies. A cake costs $5 and a pie costs $7. In one day, the store sold 15 baked goods for a total of $91. How many cakes did they sell?
-I know the answer is 7, but how do you solve it? What's the work?
Thanks.

Answer 1

Answer:

7 cakes and 8 pies

Step-by-step explanation:

To solve, write two equations: one for the total number and the other for the total sales.

Let c be the number of cakes.

Let p be the number of pies.

So c + p =15, the total sold.

And 5c + 7p = 91 for the total $ sales.

Solve by substitute one equation into another.

c + p = 15 becomes c = 15 - p. Substitute it into 5c + 7p = 91.

5(15-p) + 7p = 91

75 - 5p + 7p = 91

75 + 2p = 91

2p = 16

p=8

To find c, substitute p=8 into c = 15 - p.

c = 15 - 8

c = 7