Question

A shoppers discount club charges a monthly fee of $15 and sells gasoline for $3.55 per gallon. The gas station across the street sells gasoline for $3.85 per gallon in charge is no fee. How many gallons of gasoline would you have to buy in one month to spend the same amount at either store? Write an equation to model the situation. Then solve.

Answer 1

a. 15 + 3.55x = 3.85x b. 50 gallons

Explanation:

a. Let x be the number of gallons of gasoline bought in the one month which makes the amount the same in either store.

The amount it costs to buy x gallons of gasoline in the shoppers discount club is 15 + 3.55x and the amount it costs to buy x gallons of gasoline in the gas station is 3.85x.

Since the amount is supposed to be the same after x gallons, we have that

15 + 3.55x = 3.85x

b. Solving this equation for the gallons of gasoline, x we find that

15 + 3.55x = 3.85x

collecting like terms, we have

15 = 3.85x - 3.55x

15 = 0.30x

x = 15/0.30

x = 50 gallons

So, they must buy 50 gallons of gasoline to spend the same amount in one month.