PUZZLER

'A few weeks ago I experienced one of those rare and wonderful mornings where you just kind of wake up naturally, no alarm clocks, no noise, no nothing. Just gentle sunlight caressing my face and whispering, 'Wake up, Charlie. Wake up.'

'I rolled over and glanced at the digital clock on my nightstand and it was flashing 7:25. I thought the power must have gone off during the night. Not to worry. It's Saturday and I don't have to work. With any luck I've slept right through Car Talk. Then it hit me like a sumo wrestler falling on my chest. It wasn't Saturday after all, it was Friday! I'm going to be late for work. Again!

'So I sprang to my feet and grabbed the wristwatch off my dresser. It said 6:50. That's odd. So I ran to the kitchen where I have one of those old fashioned analog electric clocks, the kind with the hands that plugs into an electric outlet. And it read 6:30. So assuming that all three timepieces are working properly and they were all set to the same time when I went to bed the night before, when did the power go off and for how long?'

Here's the answer. Obviously the wristwatch was unaffected by the power outage so it must show the correct time which is 6:50. Now while both the analog and digital clocks were affected by the outage, they were affected differently. The analog clock simply stopped for the duration of the outage and resumed when the power came back on, so the difference between the wristwatch and the clock in the kitchen is 20 minutes. So the power was out for 20 minutes. That?s the easy part.

Here's the tough part. Most digital clocks recycle to midnight after an outage. And that's what his did, the fact that his digital clock time is later than the wristwatch must mean the digital clock was advanced as a result of the outage. So the outage must have occurred before midnight. It occurred at 11:05. How do we know that? Well, because at 11:25 when the power came back on 20 minutes later, it got advanced 35 minutes right to midnight