Phan fills the tank of her car with gasoline before starting her road trip. The table shows the amount of gas left in her tank as she drives. Number of Hours vs. Amount Left in Tank Number of Hours Spent Driving h 3 5 7 9 Amount of Gas Left in Tank, in gallons g 12 8 4 0 Which equation models the amount of gas left in the car as Phan drives, and how many gallons of gasoline does it take to fill her tank?
Answer
A
g is equal to 18 minus 2 h ; 18 gallons
B
g is equal to 3 h plus 3 ; 12 gallons
C
g is equal to 3 h plus 3 ; 30 gallons
D
g is equal to 18 minus 2 h ; 16 gallons
Explanation
The gas decreases by 4 gallons every 2 hours, so the rate is 2 gallons per hour and the equation has slope −2. Using the point (3, 12), the starting amount is 12 + 2(3) = 18 gallons, giving g = 18 − 2h. So the model is g = 18 − 2h, and the tank holds 18 gallons when full.
AI-written and checked against the verified answer.