Well?

It would be 3 and 4 simultaneously if its dripping.

3 and 4 at the same time

user,

We did this thread yesterday, please kill yourself.

P.S.

The answer is that three and 4 will be full at the same time.

If its fast then one, if its slow then 3 and 4 at the same time

Ding ding ding

These are correct

If its slow 3 and 4 at same time

If its fast 1 first.

There is also a speed inbetween that would allow 3 to fill first.

...

I don't understand why people think 3 and 4 fill at the same time. This is only true at really, really low flowrates. 3 will fill first because the water goes into 3 before it goes into 4. The driving force between 3 and 4 is a pressure difference water from 3 can only flow into 4 if it has slightly more pressure. Frictional losses compound this fact and 3 would fill before 4. At a moderate flowrate 3 will fill first.

4 can't get water in it until 3 is already full.

Let flow of water be F where F can be from 0 to highest flow rate allowed from tap.

At extremely slow speed 3 and 4 will fill at same time.

At same certain flow rate 3 will fill up first.

At an even faster flow rate 1 will fill first.