Question

An airport limo service charges riders a fixed charge of $15 plus

$4.00 per mile. How many miles must a rider go to have an
average cost per mile of $4.60?

Answer 1

Given:

An airport limo service charges riders a fixed charge of $15 plus $4.00 per mile.

To find:

Distance in miles must a rider go to have an average cost per mile of $4.60.

Solution:

Let x be the number of miles the rider travel.

Total charges = Fixed charges + Variable charges

According to the question,

Fixed charges = $15

Variable charges = $4x

So, total charges

`T=15+4x`

Divide the total charges by number of miles to get the cost per mile.

`\text{Cost per mile}=(15+4x)/(x)`

Average cost per mile is $4.60.

`4.60=(15+4x)/(x)`

`4.60x=15+4x`

`4.60x-4x=15`

`0.60x=15`

Divide both sides by 0.60.

`x=(15)/(0.60)`

`x=25`

Therefore, the required number of miles is 25.