Q:

A water reservoir has two inlets and one outlet. Through the inlet it can be filled in 3 hours and 3 hours 45 minutes respectively. It can be emptied completely in 1 hour by the outlet. If the two inlets are opened at 01 : 00 pm and 02 : 00 pm respectively and the outlet at 03 : 00 pm then it will be emptied at : 

• 1
  05 : 55 pm
• 2
  05 : 00 pm
• 3
  05 : 20 pm
• 4
  05 : 30 pm