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Brainteasers

The watch that gains three minutes an hour

clocksratesproportion

A watch is set to the correct time at noon. It runs fast at a steady rate: for every 60 minutes of real time, the watch advances 63 minutes.

When the watch reads 3:30 pm, what is the real time?

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The watch reading is not "real time plus 3 minutes per hour of watch time"; it is proportional. Set up the ratio 63 watch-minutes to 60 real minutes.

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