Which Tank Will Fill Up First?

Okay, Let’s get started here!

That was easy, it couldn’t go to D. It’s blocked. 

Looks like C is out of the question, same with J and L.

Okay, here’s the trick. I and K are out. Why? Because water will move to where there’s least resistance. J will remain level until the pressure is greater than a full container.

The answer is “F”!