Can you tell which of the black plastic water tank will fill up first ? There are a total of 12 water tanks from 0 to 11.

Tank number 7

Explanation
The connecting pipe from Tank 0 to 1, then from Tank 1 to 3 & from tank 3 to 7 is on the bottom of the upper tank. So as water enters the tank it immediately flows to next tank. But the connecting pipe from 7 to 10 is on upper side of tank 7. So only after filling tank 7, it flows to next tank 10.

1. Wrong, it will reach the base of the pipe out of 7... it won't fill which is past the top of the pipe until the two from that have filled. There for 11... it maybe nearly full when it starts to feed the others.. but it won't be full..nearly isn't fully

2. Wrong. 11 will fill first.. 100%...
Then
7 will fill.bze in intially 7 remains unfilled as much diameter of pipe takes area....
So
I request the blogger to change the answer..

3. Truely wrong........

4. This comment has been removed by the author.

6. Stewert kinsey is right... 7 is wrong answer

7. According to condition and diagram 11 is right answer only

8. 11 is right

9. If 7 fills up first, then what tank fills next? Show the order of tanks filling if 7 is first. In my opinion 11 fills first. Here is my opinion- 11-10-7-8-9-6-5-4-3-2-1-0

10. It all depends on the "Definition" of "Fills Up". If you suggest that it fills up ONLY to the connecting Pipe, then 7 would be correct. If you are Really and seriously talking about "Filling the containers" then that MUST be "FILLED TO THE BRIM" and ONLY number 11 would be FILLED to the BRIM before anoy of the other containers.

11. Look close... The outlet pipe on 7 is NOT into the tank but laying on top! 7 is the correct answer.