a certain car can travel 40 minutes on a gallon of gasoline at 80 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 80 mph ?
"total time for travelling 80 miles @ 60 mph = 80 / 80 = 1 hour = 60 minutes . given , the car uses 1 gallon for every 40 minutes of driving @ 80 mph . thus in 60 minutes it will use = 1.5 gallons . thus , full tank = 1.5 + 8 = 9.5 gallons - - - > 1.5 / 9.5 = 16 % of the fuel used . b is the correct answer ."
divide(divide(multiply(40, 80), multiply(80, 80)), add(divide(multiply(40, 80), multiply(80, 80)), 8))