Answer: 4 hours
Step-by-step explanation:
First, we will write an equation for Darla's Surf Shop. Let y be the total cost and x be the number of hours rented;
y = 4.5x + 8.25
Next, we will substitute $26.25, the cost of Shawna's Surf Shop, into the equation for Darla's as y, the total cost;
y = 4.5x + 8.25
(26.25) = 4.5x + 8.25
18 = 4.5x
4 = x
At four hours the two surf shops will charge the same amount.