Answer:
They refilled their popcorn 5 times.
Explanation:
First, set up an equation.
y = mx + b
y is the total money spent
m is the cost for each refill
x is the amount of times the popcorn is refilled
b is the start price / the price to buy the popcorn
7.40 = (0.85)x + 3.15
To solve for x, first subtract 3.15 from both sides.
4.25 = 0.85x
Now to isolate x, divide both sides by 0.85.
x = 5
They refilled their popcorn 5 times.
Before moving on, check your answer by plugging in x = 5 into the original equation.
7.40 = (0.85)(5) + 3.15
7.40 = 4.25 + 3.15
7.40 = 7.40
Your answer is correct.