Will give brainliest answer.
bob drives an average of 16,000 miles per year, and his car gets 20 miles per gallon of gasoline.
the average cost of gasoline is $3.20 per gallon.
he buys a new car.
in his new car, bob continues to average 16,000 miles per year, and the average cost of gasoline remains the same.
approximately how many more miles per gallon does the new car get if bob has a savings of $675 per year on gasoline?

1) In his old car:
number of gallons per year = 16000/20 = 800 gallos
cost of fuel per year = 800 x $3.2 = $2560

2) In his new car, the mileage of 16000 remains the same and the cost per gallon $3.2 also. 
I he made a saving of $ 675, that means only the mileage per gallon changed from 20 mi/gal to x mi/gal. (x certainly is greater than 20). 
So we have to calculate the new mileage.
Let x be the NEW mileage/gallon:
a) Number of gallon per year = 16000/x
b) Cost of few per year = (16000/x).(3.2) = (2560 - 675)

= (48000/x)= 1825
(cross multiplication) → x = 48000/1825 and x = 26.3 mi/gal (NEW mi/gal)

Then, with his new car he gained 26.3 - 20 = 6.3 mi/gal (more tan with his old car)