Question

in the cafeteria all sandwich are priced the same in all drinks are priced the same a customer ordered three sandwiches and two drinks for $14.70 another customer bought two sandwiches and four drinks for $13.80 find the cost of one sandwich and the cost of one drink

Answer 1

Cost of 1 sandwich = $3.9

Cost of 1 drink = $1.5

Explanation:

Let us assume the cost of 1 sandwich = $ m

And the cost of 1 drink = $ n

Now, according to the question:

Cost of 3 sandwich + 2 drink = $14.7

⇒ 3 m + 2 n = $14.7 ..... (1)

Cost of 2 sandwich + 4 drink = $13.8

⇒ 2 m + 4 n = $ 13.8 ..... (2)

Solving both equation, we get:

Multiply (1) with -2 and add both equations, we get:

- 6 m - 4 n + 2 m + 4 n = 13 .8 -29.4

or, -4 m = -15.6

or, m = 3.9

Put m = 3.9 in 3 m + 2 n = $14.7, we get:

11.7 + 2 n = 14.7

2 n = 3 , or n = 1.5

Hence, cost of 1 sandwich = $3.9

and the cost of 1 drink = $1.5