A car travels 90 miles in 8 hours. What is its average speed?
The average speed is 11.25 mph.
How to work it out
- 1
Write down what you know: distance d = 90 miles, time t = 8 hours. You are asked for the speed v.
- 2
Use the formula speed = distance ÷ time:
- 3
Answer with the unit: 11.25 mph.
- 4
The same formula rearranged: distance = speed × time (11.25 × 8 = 90 miles) and time = distance ÷ speed (90 ÷ 11.25 = 8 hours).
LaTeX source of the formulas on this page
\[ v = \frac{d}{t} = \frac{90}{8} = 11.25\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{90}{8} = \frac{45}{4} = 11.25 \]How far at 11.25 mph
| Time | Distance |
|---|---|
| 0.5 hours | 5.625 miles |
| 1 hour | 11.25 miles |
| 2 hours | 22.5 miles |
| 3 hours | 33.75 miles |
| 4 hours | 45 miles |
| 5 hours | 56.25 miles |
Questions
What is the speed if a car travels 90 miles in 8 hours?
The average speed is 11.25 mph.
How far does it go in 3 hours at that speed?
33.75 miles.