Math and Time Riddles

Here is a list of riddles involving dates and time or mathematics, or both.

Riddle 0001

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There are many similarities between canker sores and intrusive thoughts. In fact, canker sore is to mouth as intrusive thought is to brain. Given “canker sore” = 3, “mouth” = 9, and “intrusive thought” = 160, solve for “brain.”

Solution 0001

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We are told that canker sore is to mouth as intrusive thought is to brain. Set up the proportion. Cross multiplying gives 3(brain) = 1,440. Dividing both sides by 3 gives: brain = 480.

Riddle 0002

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I recorded a video at 1:55 a.m. and listened to it at 1:10 a.m. on the same day. How is this possible?

Solution 0002

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It happened to be the day in the middle of autumn on which the clocks are turned back one hour. I recorded the song at 1:55, five minutes before the clocks fell back, and listened to it fifteen minutes later, which due to the time change was 1:10 instead of 2:10.

Riddle 0003

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Joe was born on Saturday and John was born on Monday. Their age difference is shorter than 24 hours or 86,400 seconds. How is this possible?

Solution 0003

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Their births occurred during the same weekend that daylight saving time began. Joe was born at 11:55 p.m. EST on April 6, 2002. John, being born 23 hours and 30 minutes later, was born at 12:25 a.m. EDT on April 8, 2002.