work n Time

[sixpointer]

A tank of capacity 25 liters has an inlet and an outlet tap. If both a opened simultaneity, the tank is filled in 5 minutes. But if the outlet flow rate is doubled and taps opened, the tank never gets filled up. Which of hte following can be the outlet flow rate in liters per minute.

2
6
4
3
1


I Tied in this way :-

in one min x litre is filled and y litre get empty

in one min amount filled in tank is 1/5(25)=5 litres

X-Y=5


Now condition is if outlet flow is doubled and Tank never get filled which means work done by outlet and inlet pipe in one min is same i.e x= 2y

So y=5 l/min , which is not in option

Please tell my mistake

[Rahul@gurome]

A tank of capacity 25 liters has an inlet and an outlet tap. If both a opened simultaneity, the tank is filled in 5 minutes. But if the outlet flow rate is doubled and taps opened, the tank never gets filled up. Which of hte following can be the outlet flow rate in liters per minute.

2
6
4
3
1


I Tied in this way :-

in one min x litre is filled and y litre get empty

in one min amount filled in tank is 1/5(25)=5 litres

X-Y=5


Now condition is if outlet flow is doubled and Tank never get filled which means work done by outlet and inlet pipe in one min is same i.e x= 2y

So y=5 l/min , which is not in option

Please tell my mistake

You haven't done anything wrong. The mistake is you didn't completed the solution or you didn't recognized what is asked. The question is, Which of the following can be the outlet flow rate in liters per minute. Not what is the minimum outlet flow rate? You have found the minimum outlet flow rate. Any flow rate above that will satisfy the condition: the tank never gets filled. Thus, the possible flow rate is 6.