A car travels 20 miles in 5 hours. What is its average speed?
The average speed is 4 mph.
How to work it out
- 1
Write down what you know: distance d = 20 miles, time t = 5 hours. You are asked for the speed v.
- 2
Use the formula speed = distance ÷ time:
- 3
Answer with the unit: 4 mph.
- 4
The same formula rearranged: distance = speed × time (4 × 5 = 20 miles) and time = distance ÷ speed (20 ÷ 4 = 5 hours).
LaTeX source of the formulas on this page
\[ v = \frac{d}{t} = \frac{20}{5} = 4\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{20}{5} = 4 \]How far at 4 mph
| Time | Distance |
|---|---|
| 0.5 hours | 2 miles |
| 1 hour | 4 miles |
| 2 hours | 8 miles |
| 3 hours | 12 miles |
| 4 hours | 16 miles |
| 5 hours | 20 miles |
Questions
What is the speed if a car travels 20 miles in 5 hours?
The average speed is 4 mph.
How far does it go in 3 hours at that speed?
12 miles.