Question

A sandwich shop loses $1.20 every time somebody buys a sandwich, but makes $1.80 every time somebody buys a drink. One day, the shop sells 100 drinks. Which inequality can you use to find possible numbers of sandwiches that it could sell and still make a profit of more than $100?

1.2x – 100(1.8) > 100
100(1.2) + 1.8x > 100
100(1.2) – 1.8x > 100
100(1.8) – 1.2x > 100

Answer 1

100(1.8) – 1.2x > 100

Explanation:

Answer 2

100(1.8) – 1.2x > 100

Explanation:

Profit = Gain - loss

Gain:

$1.80 for each drink sold

So

G = 1.80d

In which d is the number of drinks sold.

One day, the shop sells 100 drinks.

This means that
`d = 100` and G = 100(1.8).

Loss:

$1.20 every time somebody buys a sandwich

x sandwiches are bought. So

L = 1.2x

Which inequality can you use to find possible numbers of sandwiches that it could sell and still make a profit of more than $100?

P > 100

P = 100(1.8) - 1.2x

So

100(1.8) – 1.2x > 100