Shawn started his car(automatic shift),drove 8km and spent 2 minutes at a stop light.Rachel(driving a manual shift) started her car and drove 9km with no stops.Who used more gas?

table of gas usage

automatic manual

idiling:.16L/min .16L/min

starting:0.05L 0.05L

moving:1L/22km 1L/20km

In 8 km, Shawn used 0.364 L (22/8)

He stopped at a light and used 0.32 L (.16 * 2).
His total liters was 0.684 L

In 9 km, Rachel used 0.45 L (9/20)

Shawn

To determine who used more gas, we need to calculate the gas usage for both scenarios.

Shawn:
- Starting the car: 0.05L
- Driving 8km: 8km * (1L/22km) = 0.36L
- Idle time (2 minutes): 2 minutes * (0.16L/min) = 0.32L

Total gas usage for Shawn: 0.05L + 0.36L + 0.32L = 0.73L

Rachel:
- Starting the car: 0.05L
- Driving 9km: 9km * (1L/20km) = 0.45L

Total gas usage for Rachel: 0.05L + 0.45L = 0.50L

Therefore, Shawn used more gas than Rachel.