Question

A hot tub is being filled with water at a rate of 50 gallons per hour. Marcia's hot tub holds 400 gallons of water. The function H(x) = 400 – 50x represents the total amount of water still needed to completely fill the hot tub. How many hours has it been filling it is still has 150 gallons to go? *

Answer 1

5 hours

Explanation:

Given the expression for the amount of water needed to completely fill the hot sub expressed as;

H(x) = 400 – 50x

x is the total number of hours

To get the number of hours it has been filling if it is still has 150 gallons to go, we will substitute h(x) as 150 and find x as shown;

150 = 400 - 50x

150 - 400 = -50x

-250 = -50x

x = -250/-50

x = 5

Hence it has been filling for 5 hours