A wall clock strikes once at 1 o'clock, twice at 2 o'clock, and so on, up to twelve times at 12 o'clock. It also strikes exactly once at every half-hour mark (e.g., 1:30, 2:30). How many total strikes does it make between 12:15 PM and 3:45 PM on the same afternoon?
10 strikes
The half-hour and hour marks in this timeframe are: 12:30 (1 strike), 1:00 (1 strike), 1:30 (1 strike), 2:00 (2 strikes), 2:30 (1 strike), 3:00 (3 strikes), and 3:30 (1 strike). Summing these gives 1 + 1 + 1 + 2 + 1 + 3 + 1 = 10 strikes.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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