My cup runneth over...

[walt]

Since its a forum, a simple question can only be answered with a whole bunch of other questions so we know exactly where you are coming from

What is the viscosity of the fluid?
What are the containers made of?
What is this is air or vacuum or nitrogen?
Is there gravity?
What is your social security number?
What is the color of the liquid?
How were the numbers for the cups chosen?
What is your favorite beverage?
Where do you sail and how often?

 

[Justin_NSA]

Where are these "blocks"? I looks to me like 6 will fill first and overflow until the liquid is shut off

 

[justsomeguy]

Where are these "blocks"?

Here's blockage #1:

 

[Justin_NSA]

Here's blockage #1:
View attachment 141997

ah, that changes everything. It's 5!

 

[Parsons]

Since its a forum, a simple question can only be answered with a whole bunch of other questions so we know exactly where you are coming from

What is the viscosity of the fluid?
...

Considering the forum ... I'd also like to remind everyone that doing this experiment yourself is very dangerous - you'll probably drown. Certainly, not performing it in a seamanlike fashion will result in hypothermia. If you must do it, please hire a professional at $90 an hour, and have adequate insurance. Did I mention the fire hazard?

 

[BlowMeAway]

Methinks this puzzle is simply a test of visual acuity and perception. There is really little fluid dynamics going on with this puzzle, and I simply refused to respond...at first. A blockage eliminates water flow, it’s all in the observation being made, not a mistake of the graphic image. Some smart person develops these puzzles to determine our interpretations. Too much brain power is not needed. This one is actually easier that the Question “Who is buried in Grant’s tomb”. Come on @Brian D, let’s have some more...

 

[BlowMeAway]

Oh yeah, the answer is clearly 5, unless the inflow exceed the outflow, and everything spills on the void. I had to add this for Post 700.