An outlet pipe empties a tank which is full in 5 hours. If the inlet pipe is kept open, which lets water in at the rate of 8 litres/min then outlet pipe would take 3 hours longer. Find the capacity of the tank.
Choose the correct choice from the following choices:
A) 8600 litres
B) 200 litres
C) 12800 litres
D) 6400 litres
E) 13200 litres
Let the rate of outlet pipe be x liters/hour;   Rate of inlet pipe is 8 litres/min, or  8*60= 
<gadget id="calculator"> 8*60</gadget>
<output>480</output>
480 liters/hour;   Net outflow rate when both pipes operate would be x-480 liters/hour.   Capacity of the tank= x*5 hours = (x-480)*(5+3) hours   5x=(x-480)*8 --&gt; x=1280 --&gt; capacity = 5x = 6400 liters.   Answer: 6400 litres
<result>D</result>
An outlet pipe empties a tank which is full in 5 hours. If the inlet pipe is kept open, which lets water in at the rate of 8 litres/min then outlet pipe would take 3 hours longer. Find the capacity of the tank.