Question

A group of 18 people ordered soup and sandwiches for lunch. Each person in the group had either one soup or one sandwich. The sandwiches cost $7.75 each and the soups cost $4.50 each. If the total cost of all 18 lunches was $113.50, how many sandwiches were ordered?
a. 7B. 8C. 9D. 10

Answer 1

x - the number of sandwiches
y - the number of soups

$x+y=18 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\times (-4.5) \\ 7.75x+4.5y=113.5 \\ \\ -4.5x-4.5y=-81 \\ \underline{7.75x+4.5y=113.5} \\ 7.75x-4.5x=113.5-81 \\ 3.25x=32.5 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\div 3.25 \\ x=10$

10 sandwiches were ordered. The answer is D.

Answer 2

Answer:

D

Step-by-step explanation: