A car travels 270 miles in 4 hours. What is its average speed?

The average speed is 67.5 mph.

v = \frac{d}{t} = \frac{270}{4} = 67.5\ \text{mph}

How to work it out

1
Write down what you know: distance d = 270 miles, time t = 4 hours. You are asked for the speed v.
2
Use the formula speed = distance ÷ time:
$v = \frac{d}{t} = \frac{270}{4} = \frac{135}{2} = 67.5$
3
Answer with the unit: 67.5 mph.
4
The same formula rearranged: distance = speed × time (67.5 × 4 = 270 miles) and time = distance ÷ speed (270 ÷ 67.5 = 4 hours).

LaTeX source of the formulas on this page

\[ v = \frac{d}{t} = \frac{270}{4} = 67.5\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{270}{4} = \frac{135}{2} = 67.5 \]

What is the speed if a car travels 270 miles in 4 hours?

The average speed is 67.5 mph.

How far does it go in 3 hours at that speed?

202.5 miles.