A car travels 390 miles in 10 hours. What is its average speed?
The average speed is 39 mph.
How to work it out
- 1
Write down what you know: distance d = 390 miles, time t = 10 hours. You are asked for the speed v.
- 2
Use the formula speed = distance ÷ time:
- 3
Answer with the unit: 39 mph.
- 4
The same formula rearranged: distance = speed × time (39 × 10 = 390 miles) and time = distance ÷ speed (390 ÷ 39 = 10 hours).
LaTeX source of the formulas on this page
\[ v = \frac{d}{t} = \frac{390}{10} = 39\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{390}{10} = 39 \]How far at 39 mph
| Time | Distance |
|---|---|
| 0.5 hours | 19.5 miles |
| 1 hour | 39 miles |
| 2 hours | 78 miles |
| 3 hours | 117 miles |
| 4 hours | 156 miles |
| 5 hours | 195 miles |
Questions
What is the speed if a car travels 390 miles in 10 hours?
The average speed is 39 mph.
How far does it go in 3 hours at that speed?
117 miles.