Question

The Nisbets went through the drive through

at the donut shop and spent $10.50 on 2
cups of coffee and 4 donuts. Behind them,
the Roys spent $8.25 on 1 cup of coffee and
5 donuts. What is the cost of one cup of
coffee?

Answer 1

One cup of coffee is $3.25

Explanation:

Create a system of equations where c is the cost of a cup of coffee and d is the cost of a donut

2c + 4d = 10.5

c + 5d = 8.25

Solve by elimination by multiplying the top equation by -5 and the bottom equation by 4

-10c - 20d = -52.5

4c + 20d = 33

Add them together and solve for c

-6c = -19.5

c = 3.25

So, a cup of coffee is $3.25