Answer:
$5.5 per mile
40 miles
Explanation:
Given :
Fixed cost = $10
Variable cost = $3
For a journey of 4 miles ;
Cost = fixed cost + Variable Cost
Cost = $10 + $3x
x = number of miles
Cost = $10 + $3(4)
Cost = $10 + $12 = $22
Average cost per mile for a journey of 4 miles
Cost / number of miles
$22 / 4 = $5.5 per mile
Minimum distance if average per mile is to be less Than 3.25
$3.25 = (10 + 3x) / x
3.25x = 10 + 3x
3.25x - 3x = 10
0.25x = 10
x = 10 / 0.25
x = 40 miles