A car travels 20 miles in 7 hours. What is its average speed?
The average speed is 2.8571429 mph.
How to work it out
- 1
Write down what you know: distance d = 20 miles, time t = 7 hours. You are asked for the speed v.
- 2
Use the formula speed = distance ÷ time:
- 3
Answer with the unit: 2.8571429 mph.
- 4
The same formula rearranged: distance = speed × time (2.8571429 × 7 = 20 miles) and time = distance ÷ speed (20 ÷ 2.8571429 = 7 hours).
LaTeX source of the formulas on this page
\[ v = \frac{d}{t} = \frac{20}{7} = 2.8571429\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{20}{7} = \frac{20}{7} = 2.8571429 \]How far at 2.8571429 mph
| Time | Distance |
|---|---|
| 0.5 hours | 1.4285714 miles |
| 1 hour | 2.8571429 miles |
| 2 hours | 5.7142857 miles |
| 3 hours | 8.5714286 miles |
| 4 hours | 11.428571 miles |
| 5 hours | 14.285714 miles |
Questions
What is the speed if a car travels 20 miles in 7 hours?
The average speed is 2.8571429 mph.
How far does it go in 3 hours at that speed?
8.5714286 miles.