Q3.

Pipes P and Q can fill a storage tank in full with water in 10 and 6 minutes, respectively. Pipe R draws the water out from the storage tank at a rate of 34 litres per minute. P, Q and R operate at a constant rate. 
If it takes one hour to completely empty a full storage tank with all the pipes operating simultaneously, what is the capacity of the storage tank (in litres)?

Q4.

Six persons P, Q, R, S, T and U are sitting around a circular table facing the center not necessarily in the same order. Consider the following statements: 
• P sits next to S and T. 
• Q sits diametrically opposite to P. 
• The shortest distance between S and R is equal to the shortest distance between T and U. 
Based on the above statements, Q is a neighbor of

Q5.

A building has several rooms and doors as shown in the top view of the building given below. The doors are closed initially. 
What is the minimum number of doors that need to be opened in order to go from the point P to the point Q?