Hi Candidate,

In this given Question, it's mentioned that the sheet of dimensions- 2 dm and 1.5 dm are travelling in speed of 15 km/hr. It has to pass through the tank of dimensions- 23dm * 37dm *40dm. So, the given length of the tank= 23*37*40/ (2*1.5)= 11,346.66 dm = 11.346 km. So, the time needed to cross the tank= 11.346/15= .756 hours= 38.56 minutes.

Hope that this answer helps you.