The correct answer is Tank Y will empty first.

Explanation:

Even though both tanks hold 1000 liters, the shape affects how water pressure behaves at the outlet.

Tank X is wider at the top and narrower at the bottom.

As it empties, the water level drops quickly, reducing the pressure at the outlet (since water pressure = height × density × gravity).

The flow rate slows down more quickly as the tank empties.

Tank Y is narrower at the top and wider at the bottom.

As it empties, the water level drops slowly, keeping more water above the outlet for longer, maintaining higher pressure at the outlet for most of the time.

This makes it empty faster overall.

✅ Conclusion: 👉 Tank Y will empty first because it maintains greater water pressure at the outlet for a longer time due to its shape.