The tank-full petrol in Arun's motor-cycle lasts for 10 days. If he starts using 25% more everyday, how many days will the tank-full petrol last?
Assume 100 litres of petrol in bike.
So, for 10 days, 10 litres is required daily.
Now using 25% more everyday means 12.5 litres of petrol.
100/12.5 = 8
The correct option is D.