A car travels 140 km in 9 hours. What is its average speed?

The average speed is 15.555556 km/h.

v = \frac{d}{t} = \frac{140}{9} = 15.555556\ \text{km/h}

How to work it out

1
Write down what you know: distance d = 140 km, time t = 9 hours. You are asked for the speed v.
2
Use the formula speed = distance ÷ time:
$v = \frac{d}{t} = \frac{140}{9} = \frac{140}{9} = 15.555556$
3
Answer with the unit: 15.555556 km/h.
4
The same formula rearranged: distance = speed × time (15.555556 × 9 = 140 km) and time = distance ÷ speed (140 ÷ 15.555556 = 9 hours).

LaTeX source of the formulas on this page

\[ v = \frac{d}{t} = \frac{140}{9} = 15.555556\ \text{km/h} \]
\[ v = \frac{d}{t} = \frac{140}{9} = \frac{140}{9} = 15.555556 \]

What is the speed if a car travels 140 km in 9 hours?

The average speed is 15.555556 km/h.

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

46.666667 km.