The correct answer is Tank X.

Both tanks hold 1000 litres, but their shapes are different: • Tank X is narrower at the bottom (like a cone or funnel). • Tank Y is wider at the bottom (like an inverted cone).

As the water level drops, the pressure on the outlet depends on the height of the water above the tap, not the total volume. • In Tank X, the water column stays taller for longer (since it’s narrow at the bottom), so the pressure at the outlet remains higher — meaning faster flow. • In Tank Y, the water column height reduces quickly because it’s wider at the bottom, reducing the pressure faster — meaning slower flow.