Jess's driving millege

Question

Jess started driving with a full tank of gas the tank holds 15 gallons after driving 200 miles she looks at the gauge and sees she has exactly two-thirds of a tank of gas left

Answer 1

You know that Jess is driving with a full tank of 15 gallons.  After 200 miles of driving she still has 2/3 of a full tank, so she only used up 1/3 of her tank.  1/3 x 15 = 5 gallons used.

 

If 5 gallons took her a total distance of 200 miles then you divide the two numbers (200/5) to get miles per gallon.

 

Jess's driving mileage is 40 miles per gallon.

Answer 2

(200 miles)(1 tank/15 gallons)(1/((1-2/3) tank)) = 200/5 = 40 mpg