The first step to find the answer is to convert the miles he run to feet, using the conversion factor given in the statement:
[tex]5miles\cdot\frac{5280ft}{1mile}=26400ft[/tex]
Now, divide this number by 40 (this is because his neighbor is going to pay for every 40 feet):
[tex]\frac{26400ft}{40ft}=660[/tex]
Now, multiply this number by $0.25 and then add it to the product of 5 and $18 (which is the amount paid by his aunt for every mile run):
[tex]0.25\cdot660+18\cdot5=255[/tex]
