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The Water Jug Riddle: Measure It With Just a 5L and a 3L Jug
You have a 5-litre jug, a 3-litre jug, and unlimited water. You want to measure exactly 4 litres. What volume remains in the 5-litre jug after the final step?
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What is the answer to the 5-litre and 3-litre water jug riddle?
After the final step, 4 litres remain in the 5-litre jug. Steps: fill the 5L, pour into the 3L (2L left in the 5L), empty the 3L, pour the 2L into the 3L, refill the 5L, then top up the 3L from the 5L — 4 litres are left in the 5L jug.
How do you measure 4 litres with a 5-litre and a 3-litre jug?
Fill the 5L jug, pour into the 3L until it's full (leaving 2L), empty the 3L, transfer those 2L into the 3L, refill the 5L, then pour into the 3L until it's full again. Exactly 4 litres stay in the 5L jug.
Is the water jug riddle hard?
It's a medium-difficulty logic puzzle. There's no trick — just six careful pour-and-empty steps. Once you see the sequence, it feels obvious.