A car travels 90 miles in 5 hours. What is its average speed?
The average speed is 18 mph.
How to work it out
- 1
Write down what you know: distance d = 90 miles, time t = 5 hours. You are asked for the speed v.
- 2
Use the formula speed = distance ÷ time:
- 3
Answer with the unit: 18 mph.
- 4
The same formula rearranged: distance = speed × time (18 × 5 = 90 miles) and time = distance ÷ speed (90 ÷ 18 = 5 hours).
LaTeX source of the formulas on this page
\[ v = \frac{d}{t} = \frac{90}{5} = 18\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{90}{5} = 18 \]How far at 18 mph
| Time | Distance |
|---|---|
| 0.5 hours | 9 miles |
| 1 hour | 18 miles |
| 2 hours | 36 miles |
| 3 hours | 54 miles |
| 4 hours | 72 miles |
| 5 hours | 90 miles |
Questions
What is the speed if a car travels 90 miles in 5 hours?
The average speed is 18 mph.
How far does it go in 3 hours at that speed?
54 miles.