a certain car can travel 20 minutes on a gallon of gasoline at 60 miles per hour . if the car had started with a full tank and had 8 gallons of gasoline left in its tank at the end , then what percent of the tank was used to travel 80 miles at 60 mph ?
"let , tank capacity = t gallon used fuel = ( t - 8 ) gallons distance travelled ( @ 60 miles / hr ) = 80 miles distance travelled in 1 gallon = distance travelled in 20 mins ( @ 60 miles / hr ) = ( 60 / 60 ) * 20 = 20 miles fuel used to travel 80 miles = ( 80 / 20 ) = 4 gallon i . e . used fuel = ( t - 8 ) = 4 gallon i . e . t = 12 gallons i . e . used fuel = ( 2 / 12 ) * 100 = 16,67 % a"
divide(divide(multiply(20, 60), multiply(80, 60)), add(divide(multiply(20, 60), multiply(80, 60)), 8))