Amit travelled black to home in a car, after visiting his friend in a distant village. When he stated at his friend's house the car had exactly 18 litres of petrol in it. He travelled along at a steady 40 kilometres per hour and managed a 10 kilometres per litre of petrol. As the car was old, the fuel tank lost fuel at the rate of half a litre per hour. Amit was lucky as his car stopped just in front of his home because it had rum out of fuel and he only just made it. How far was it from his friend's home to Amit's home ?

A. 150 km

B. 170 km

C. 180 km

D. None of these

Answer: Option D

Solution(By Examveda Team)

Quantity of petrol consumed in 1 hour:
$$\eqalign{ & = \left( {\frac{{40}}{{10}} + \frac{1}{2}} \right){\text{ litres}} \cr & = 4\frac{1}{2}{\text{ litres}} \cr} $$
Time for which the fuel lasted :
$$\eqalign{ & = \left[ {\frac{{18}}{{\left( {4\frac{1}{2}} \right)}}} \right]{\text{ hrs}} \cr & = \left( {18 \times \frac{2}{9}} \right){\text{ hrs}} \cr & = 4{\text{ hrs}} \cr} $$
∴ Required distance = (40 × 4) km = 160 km