For a 1.5 hour flight with 0.75 hour reserve and a burn rate of 6 GPH, how many gallons total are needed?

For a 1.5 hour flight with 0.75 hour reserve and a burn rate of 6 GPH, how many gallons total are needed?

• A. 9 gallons
• B. 13.5 gallons
• C. 7.5 gallons
• D. 6 gallons

Answer: (A)

Fuel needed comes from burn rate times total time aloft. The burn rate is 6 gallons per hour, and the total time is the flight time plus the reserve: 1.5 hours + 0.75 hour = 2.25 hours. Multiply 6 by 2.25 to get 13.5 gallons. So you’d need 13.5 gallons in total. If you only used the flight time, you’d have 9 gallons (6 × 1.5), which doesn’t cover the reserve. The other options correspond to shorter times (for example, 7.5 gallons is 6 × 1.25 hours, and 6 gallons is 6 × 1 hour). The key is including the reserve when calculating total fuel.

Fuel needed comes from burn rate times total time aloft. The burn rate is 6 gallons per hour, and the total time is the flight time plus the reserve: 1.5 hours + 0.75 hour = 2.25 hours. Multiply 6 by 2.25 to get 13.5 gallons. So you’d need 13.5 gallons in total. If you only used the flight time, you’d have 9 gallons (6 × 1.5), which doesn’t cover the reserve. The other options correspond to shorter times (for example, 7.5 gallons is 6 × 1.25 hours, and 6 gallons is 6 × 1 hour). The key is including the reserve when calculating total fuel.