An hourglass takes 7 minutes to empty completely. If you invert it immediately after it empties, how many total minutes will have passed when it empties again?
Category: Math · Difficulty: expert
Hint: Think about overlapping intervals.
Answer
14
Explanation
The first run takes 7 minutes, then the second run takes another 7, totaling 14 minutes.
This is a expert math riddle — one of the harder riddles here. The answer is 14.
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