Linear Equations of Problem Scenarios

Question

Miss Johnson received a $50 gift card to Starbucks for her birthday. Her favorite drink, strawberry-Açaí refresher, costs $4.50. Miss Johnson uses her gift card to purchase her drinks. Write an equation that represents this situation.

Answer 1

Hi, Elizabeth,

I agree with Puneet's answer. His equation would also tell you how many acai drinks she can purchase with the $50 card:

If she spent everything, y = 0.

Therefore: 0 = 50 - 4.50x

-50 = -4.50x

x = 11.11 . . .

Since x is limited to a whole number, we round down to 11, the number of drinks that can be purchased. That would leave $0.50 on her card.

One must question her choice of drink at a Starbucks, however. Give her card to me and it will go for coffee. That is because of a little-known equation:

:)

Bob

Answer 2

The wording seems strange but I'm going to assume her drinks means number of acai drinks, which we will represent with x.

y will be money left on her gift card

y = $50 - $4.50x