Question

Two customers purchased coffee and doughnuts at a coffee shop. Each cup of coffee costs the same amount, and each doughnut costs the same amount.

The first customer paid $4.90 for 1 cup of coffee and 2 doughnuts.
The second customer paid $8.60 for 2 cups of coffee and 3 doughnuts.
What is the cost of 1 cup of coffee?
A
$2.50
B
$1.20
C
$4.90
D
$3.70

Answer 1

Let c = cost of a coffee and d = cost of a doughnut.

From the purchases:
c + 2d = 4.90
2c + 3d = 8.60

Multiply the first by 2: 2c + 4d = 9.80. Subtract the second:
(2c+4d) − (2c+3d) = 9.80 − 8.60 → d = 1.20.

Plugging back: c + 2(1.20) = 4.90 → c + 2.40 = 4.90 → c = 2.50.

Answer: A ($2.50).