At first glance, both tanks look the same: same capacity, same outlet, same water level. But there’s one key detail that completely changes the result… and very few people notice it on the first try. The shape of the container directly influences how the water flows over time, creating a difference that ends up being decisive.
This curious challenge has gotten many people thinking and has generated all kinds of answers. Do you think you know which one empties first? Before you answer, look closely at every detail… because the answer might not be what you imagine. Find out here.
A: Tank X empties first.
The reason is physical: the hydrostatic pressure at the water outlet. In Tank X, since it is narrower at the base and has an inverted conical shape, the weight of the water exerts greater downward pressure on the outlet (the faucet), which makes the water flow out faster.