Two pipes P and Q can fill an empty tank in 25 hours and 20 hours respectively. Pipe R alone can empty the completely filled tank in 50 hours. Firstly both the pipes P and Q are opened and after 8 hours pipe R is also opened. What will be the total time (in hours) taken to completely fill the tank?
If the amount received at the end of 2nd and 3rd year at Compound Interest on a certain Principal is Rs 32448 and Rs 33745.92 respectively, what is the rate of interest?