A car goes 15 km on a gallon of octane. When it is 50 km/h. When the car is driven at 60 km/h, it only goes 80% as far. How many gallons of octans are needed to travel 200 km it half the distance is traveled at 50 km/h and the rest 60 km/h ?

Correct Answer: 15.00
At 50km/h 15 km needs 1 gallon So, 100 km needs 100/15 gallon At 60km/h, It goes 80% far = 80% of 15 = 12 km 12 km needs 1 gallon So, 100 km needs 100/12 gallon So, (100 + 100) = 200 km needs = (100/15 + 100/12) gallon = (400 + 500)/60 gallon = 900/60 gallon = 15 gallon