Gasoline varies in cost from $0.95 to $1.15 per gallon. If a car’s mileage varies from 16 to 24 miles per gallon, what is the difference between the most and least that the gasoline for a 480-mile trip will cost?
Select the correct option.
A) $15.50
B) $15.72
C) $16.10
D) $16.50
E) $17.01
Solution:   We know that the per gallon cost of gasoline varies from $0.95 - $1.15.   Now we want to find the MAXIMUM difference between the least amount of money spent on gasoline and the largest amount of money spent i.e. to calculate max. trip cost - min. trip cost.   Mileage is given to be 16 to 24 miles per gallon, thus to travel 480 miles you will need gasoline in the range 480/24 to 480/16 which is 20 to 30 gallons.   So, for these 20 gallons and 30 gallons of gasoline the cost is as follows: (divide this task into 2 parts, 1 for 30 gallons and 2nd one for 20 gallons).   Case 1: for 30 gallons the cost is 30*0.95 to 30*1.15 which is $28.50 to $34.50   Case 2: for 20 gallons the cost is 20*0.95 to 20*1.15 which is $19.00 to $23.00   Thus, the maximum cost of the 480 mile trip is $34.50 and minimum is $19.00   so the difference is $34.50 - $19.00 = $15.50   $15.50nswer: $15.50 34.50 -  19.00= 
<gadget id="calculator"> 34.50 -  19.00</gadget>
<output>15.5</output>
$15.50   $15.50nswer: $15.50
<result>A</result>
Gasoline varies in cost from $0.95 to $1.15 per gallon. If a car’s mileage varies from 16 to 24 miles per gallon, what is the difference between the most and least that the gasoline for a 480-mile trip will cost?