Welcome to your daily brain workout! Today’s puzzle tests your lateral thinking. It’s a favorite in job interviews at tech companies.

🧩 Today’s Puzzle: The Hourglass Problem

You have two hourglasses: one measures exactly 7 minutes, and the other measures exactly 4 minutes. You need to time exactly 9 minutes. How do you do it using only these two hourglasses?

💡 Hint

You can flip hourglasses as many times as you want, and you can flip them mid-run. Think about what happens when you start both at the same time, then flip one when the other finishes. The difference between 7 and 4 is 3 — can you combine that with another 4+something?

📅 Yesterday’s Answer (June 24)

Puzzle: The Fox, Chicken, and Grain — what’s the crossing sequence?

✅ Answer: (1) Take chicken across, return alone. (2) Take fox across, bring chicken back. (3) Take grain across, return alone. (4) Take chicken across. Done! The trick: the chicken must come BACK on the second trip so it’s not left with the grain while you take the fox.

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