A car travels 430 miles in 8 hours. What is its average speed?

The average speed is 53.75 mph.

v = \frac{d}{t} = \frac{430}{8} = 53.75\ \text{mph}

How to work it out

1
Write down what you know: distance d = 430 miles, time t = 8 hours. You are asked for the speed v.
2
Use the formula speed = distance ÷ time:
$v = \frac{d}{t} = \frac{430}{8} = \frac{215}{4} = 53.75$
3
Answer with the unit: 53.75 mph.
4
The same formula rearranged: distance = speed × time (53.75 × 8 = 430 miles) and time = distance ÷ speed (430 ÷ 53.75 = 8 hours).

LaTeX source of the formulas on this page

\[ v = \frac{d}{t} = \frac{430}{8} = 53.75\ \text{mph} \]
\[ v = \frac{d}{t} = \frac{430}{8} = \frac{215}{4} = 53.75 \]

What is the speed if a car travels 430 miles in 8 hours?

The average speed is 53.75 mph.

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

161.25 miles.