The following question consists of a statement at question place, followed by three informative statements. You have to study the questions carefully and select the statement or statements, sufficient to validate the statement at question place.

The percentage of the filling done by tap X alone is 35%.

I. After 2 hours, tap Z is closed and X and Y are kept running as the remaining fill is done by tap X alone

II. Three pipes X, Y and Z can fill the tank in 10 hours, 20 hours and 40 hours respectively as at the beginning all of them are opened simultaneously

III. After the 4th hour, tap Y is also closed as the remaining fill is done by tap X alone