Welcome to your daily brain workout! This puzzle is another tech interview classic. It seems impossible at first — but there’s a trick.

🧩 Today’s Puzzle: The Burning Ropes

You have two ropes, each of which takes exactly 60 minutes to burn from end to end. However, the ropes burn unevenly — half the length might burn in 10 minutes, the other half in 50 minutes. You have a lighter. How do you measure exactly 45 minutes?

💡 Hint

If you light a rope from BOTH ends, it burns in 30 minutes (half the time). What happens if you combine that with a rope lit from one end? Think about how to get 30 + 15 = 45.

📅 Yesterday’s Answer (June 25)

Puzzle: The Hourglass Problem — measure 9 minutes using 7-min and 4-min hourglasses.

✅ Answer: Start both hourglasses at time 0. When the 4-min empties (4 min), flip it immediately. When the 7-min empties (7 min), the 4-min has 1 minute of sand in the top (it ran 3 min, flipped, ran 4 min — wait, let’s be precise). Better method: Start both. When 4-min empties, flip it (4 min elapsed). When 7-min empties, flip it (7 min elapsed, 4-min has 1 min of sand on top). When 4-min empties again, flip 7-min (8 min elapsed, 7-min ran 1 min so 6 min of sand on top). When 7-min empties, 9 minutes total.

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