feekman:
7

Number 7 dey leak na...haba

CarGuideNG:
Tank 7 has a hole at the bottom, so it would never get filled.

The pipe leading to tank 4 is blocked off, so tank 4 would never get filled.

The pipe leading to tank 6 is also blocked off from the major end, so tank 6 would never get filled.

The outlet of tank 3 connects to tank 7 which has a hole at the bottom, so tank 3 would never get filled.

The outlet of tank 2 from tank 1, is lower than the outlet of tank 3 from tank 1, so tank 2 would get the liquid first.

However,

Tank 2 has an outlet to tank 5, so tank 2 would never get filled.

That would leave tank 1 and tank 5

Tank 5 would get filled first.

Remember that the outlet of tank 5 is not at the brim, so tank 6 has to be filled first before 5

None. Container is sealed.

lokito:


Remember that the outlet of tank 5 is not at the brim, so tank 6 has to be filled first before 5

You need to consider the height of 6 and 5...since 5 is not as high as 6, the fluid will fill 5 first.

Cup 4

PharmaGirl:
So which one?
1, 2, 3, 4, 5, 6 or 7?
Remember, it's not as simple as it looks .

Your time starts now!

lokito:


Remember that the outlet of tank 5 is not at the brim, so tank 6 has to be filled first before 5

Tank 5 will fill tank 6 until they reach the same height as the hole. Thereafter they will rise at the same rate. Since 5 is however lower than 6, it will get filled first.

Fun fact: tank 6 will never be filled. The chanell from tank 3 is blocked leaving only the inlet from tank 5. Now tank 5 will fill tank 6 until tank 5 is filled up. At this point, tank 6 will be at the same level. Any additional fluid to tank 5 will spill as there will be no pressure to force the fluid into tank 6.
In fact, if inlet from tank 3 was opened, the result will be same as once tank 5 and 6 reach the same level, any inflow to tank 6 will overflow via tank 5.

Assumptions: fluid is water or have waterlike capillary attributes. It is also at normal atmospheric pressure.