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Tick Tock

Age 11 to 14
ShortChallenge Level Yellow starYellow star
Secondary curriculum
  • Problem
  • Solutions

Answer: 8 am on Monday

Tick's watch is 2 minutes slow per hour, Tock's is 1 minute fast per hour, so Tock's watch is faster than Tick's watch by 3 minutes per hour.

Correct time Tick's Watch Tock's Watch Difference
12:00 12:00 12:00 -
13:00 12:58 13:01 3 minutes
14:00 13:56 14:02 6 minutes

They get 3 minutes further apart after each 1 hour.

They will be 60 minutes further apart after 20 hours.

20 hours after midday on Sunday is 8 am on Monday.

 

This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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