Question

The distance traveled by a car moving at a constant speed varies directly with the length of time it travels. If the car travels 172 miles in 4 hours, how many miles will it travel in 10 hours?

Answer 1

First, we must find the unit rate in other words, we must find how much miles the car travels in 1 hour or vice-versa.
$\frac{172 \: miles}{4 \: hours} = \frac{43 \: miles}{1 \: hour}$
Now, plug in the ten instead of a 1 in the proportion of,
$\frac{43 \: miles}{1 \: hour} = \frac{430 \: miles}{10 \: hours}$
This is simply because 1*10=10 and 43*10=430.
I hope this helps!!