A car travels 390 km in 11 hours. What is its average speed?

The average speed is 35.454545 km/h.

v = \frac{d}{t} = \frac{390}{11} = 35.454545\ \text{km/h}

How to work it out

1
Write down what you know: distance d = 390 km, time t = 11 hours. You are asked for the speed v.
2
Use the formula speed = distance ÷ time:
$v = \frac{d}{t} = \frac{390}{11} = \frac{390}{11} = 35.454545$
3
Answer with the unit: 35.454545 km/h.
4
The same formula rearranged: distance = speed × time (35.454545 × 11 = 390 km) and time = distance ÷ speed (390 ÷ 35.454545 = 11 hours).

LaTeX source of the formulas on this page

\[ v = \frac{d}{t} = \frac{390}{11} = 35.454545\ \text{km/h} \]
\[ v = \frac{d}{t} = \frac{390}{11} = \frac{390}{11} = 35.454545 \]

What is the speed if a car travels 390 km in 11 hours?

The average speed is 35.454545 km/h.

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

106.36364 km.