Question

Desserts on a restaurant's adult menu cost $6 each and on the child's menu, they cost $3 each. If 160 desserts were sold on Sunday for a total of $816, how many adults ordered dessert?

A. 27
B. 48
C. 112
D. 136

Answer 1

C

Explanation:

let a be the number of adults and c the number of children.

Now set up a pair of simultaneous equations and solve for a

a + c = 160 → (1) [ based on 160 desserts being sold ]

6a + 3c = 816 → (2) [ based on cost of dessert for adult/ child ]

multiplying (1) by - 3 and adding to (2) will eliminate c

- 3a - 3c = - 480 → (3)

add (2) and (3) term by term to eliminate c

(6a - 3a) + (3c - 3c) = 816 - 480

3a + 0 = 336

3a = 336 ( divide both sides by 3 )

a = 112

That is 112 adults ordered desserts