Amit travelled back to home in a car, after visiting his friend in a distant village. When started at his friend's house the car had exactly 18 litres of petrol in it. He travelled along at steady 40 kilometres per hour and managed 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 from of his home because it had run out of fuel and he only just made it. How far was it from his friend's home to Amit's home? `150\ k m` b. `\ 170\ k m` c. `180\ k m` d. none of these