Question

If the velocity of a car is 45 kilometers per hour West, how far can it travel in 0.5 hours?

Answer 1

`x=22 1/2=22.5 km` West

Explanation:

We're told the car is going 45 kilometres per hour. We can match up the numbers with the units by writing it this way:

`45/1 "km"/"hr"`

This says that for every hour, we travel 45 kilometres.

How far do we travel if we travel for only `1/2` of an hour? One way to do that is to is to set up a ratio, where we set the time as `1/2` and we set the kilometres as `x`. Since we're still moving at the same rate, we can set the two ratios equal to each other:

`45/1=x/(1/2)`

And now let's cross multiply:

`45xx1/2=x`

`x=22 1/2=22.5 km` West