IIFT 2018 Question Paper | Quants

The best way to boost your IIFT prep is to practice the actual IIFT Question Papers. 2IIM offers you exactly that, in a student friendly format to take value from this. In the 2018 IIFT, Quants was a mixed bag of questions of varying difficulty, with some routine questions and the others were very demanding. Some beautiful questions that laid emphasis on Learning ideas from basics and being able to comprehend more than remembering gazillion formulae and shortcuts.

Question 14 : Nitin installed an overhead tank on the roof of his newly constructed house. Three taps are connected to the tank: 2 taps A and B to fill the tank and one tap C to empty it. Tap A alone can fill the tank in 12 hours, while tap B alone takes one and a half times more time than tap A to fill the tank completely. Tap C alone can empty a completely filled tank in 36 hours. Yesterday, to fill the tank, Nitin first opened tap A, and then after 2 hours opened tap B also. However after 6 hours he realised that tap C was open from the very beginning. He quickly closes tap C. What will be the total time required to fill the tank?

1. 8 hours 48 minutes
2. 8 hours 30 minutes
3. 9 hours 12 minutes
4. 9 hours 36 minutes

Explanatory Answer

A takes 12 hrs, B takes 18 hrs and C takes 36 hrs.
Total job done in 8 hours = 8/12 + 6/18 – 8/36 = 60/72
Total job left = 12/72
Time taken by A and B to do the job = (12/72)/(1/12 + 1/18) = 1.2 hrs = 1 hour 12 min
Hence total time = 9 hour 12 mins

The answer is '9 hours 12 minutes'

Choice C is the correct answer.