A car travels 10 km in 7 hours. What is its average speed?

The average speed is 1.4285714 km/h.

v = \frac{d}{t} = \frac{10}{7} = 1.4285714\ \text{km/h}

How to work it out

1
Write down what you know: distance d = 10 km, time t = 7 hours. You are asked for the speed v.
2
Use the formula speed = distance ÷ time:
$v = \frac{d}{t} = \frac{10}{7} = \frac{10}{7} = 1.4285714$
3
Answer with the unit: 1.4285714 km/h.
4
The same formula rearranged: distance = speed × time (1.4285714 × 7 = 10 km) and time = distance ÷ speed (10 ÷ 1.4285714 = 7 hours).

LaTeX source of the formulas on this page

\[ v = \frac{d}{t} = \frac{10}{7} = 1.4285714\ \text{km/h} \]
\[ v = \frac{d}{t} = \frac{10}{7} = \frac{10}{7} = 1.4285714 \]

What is the speed if a car travels 10 km in 7 hours?

The average speed is 1.4285714 km/h.

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

4.2857143 km.