Question

Carly walks 30 feet in seven seconds. At this rate, how many minutes will it take for Carly to walk a mile if there are 5,280 feet in one mile?

Answer 1

roughly `20 1/2` minutes

Explanation:

We are given a rate of walking as `(30ft)/(7 sec)` and Carly, at this rate, will walk one mile which is also given as 5280 feet. How many minutes will it take?

Let's first look at the units we have and where we want to end up:

We want minutes as our answer, so:

`"minutes"=?`

We're given a rate in `(ft)/(sec)`, but since we want to end up with time as the result, we need the time term in the numerator:

`"minutes"=(sec)/(ft)xx?`

We know the number of feet to be walked:

`"minutes"=(sec)/(ft)xxftxx?`

and what's left is a conversion factor to change seconds to minutes:

`"minutes"=cancel(sec)/cancel(ft)xxcancel(ft)xx"minutes"/cancel(sec)="minutes"`

Now let's drop in the numbers:

`"minutes"=7/30xx5280xx1/60=36960/1800=20.5bar3~~20 1/2` minutes