Water is supplied to a tank at the rate of 30 litres per minute from 1 PM to 3 PM, at the rate of 50 litres per minute from 3 PM to 6 PM, and at the rate of 45 litres per minute from 6 PM to 8 PM. Water is withdrawn from tank at a regular speed of 25 litres per minute. The tank was empty at 1 PM and became completely full at 7:20 PM. What is the capacity of tank (in litres)?
1
6300
2
5800
3
6700
4
6950
5
7200