Help with Pipe Flow: Tank Filling Proportion in 3 Hours

[allaputa]

A storage tank is replenished by an inflow pipe which can fill it in 8 hours.If the tank is initially full and the outflow pipe can empty it in 12 hours,what proportion of the tank is full after 3 hours duration?

 

[Doc Al]

What's the rate at which fluid flows into the tank? Out of the tank? (Express both rates in units of Tankfulls per hour.) What's the net rate of inflow?

 

[allaputa]

Doc not really clear about it

 

[Doc Al]

One pipe flows into the tank at a rate of 1 tank per 8 hours. Express this in Tanks/hour.

 

[I'm_PK]

Is it emptying and filling at the same time? In this case the tank would be OVERFLOWING
1/8 - 1/12 = 1/24 of the whole tank volume every hour.