A wall clock strikes once at 1 o'clock, twice at 2 o'clock, and so on. In addition, it strikes once on every half-hour. How many total strikes does the clock make in a full 24-hour day?
180
In 12 hours, the hourly strikes sum to 1 + 2 + ... + 12 = 78. In 24 hours, that is 78 × 2 = 156 strikes. Adding 24 half-hour strikes gives 156 + 24 = 180 total strikes.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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