Directions: Read the below paragraph and answer according to data given in particular question and this paragraph.

A boat speed is 15 km/h and speed of stream is 5 km/hr. Distance between A and B is 100 km and the boat is travelling between A and B. After travelling (6/10)^th of the distance boat developed a fault and it travelled with different speed afterwards. (From A to B direction is downstream and from B to A direction is upstream)