Xavier Aptitude Test 2013 Paper

(d) Time taken by Prof. Mandal to the market by Auto and walk = 90 minutes.
or, Auto + walk = 90 minutes
Time taken by Prof. Mandal to the market by Auto both ways = 30 minutes.
or, Auto + Auto = 30 minutes
∴ Auto = 15 minutes
It means that one way by auto would taken 15 minutes.
So from the round trip of 90 minutes, we get 75 minutes which is the time taken to cover one way walking.
Hence, time taken for round trip walking equals to2 × 75 minutes = 150 minutes.