A, B and C are 3 small pumps fitted to a tank. D is a large pump fitted to the tank. B is 50% more efficient than A. C is 33.33% more efficient than B. D is 50% more efficient than C. All of the pumps are used to fill the tank. Find the ratio of the time taken by all the pumps to fill the tank when pump D is used to empty the tank and other are used to fill the tank to the time taken when all are used to fill the tank?
1
4 : 1
2
3 : 2
3
5 : 2
4
5 : 1
5
None of these