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## Time Spent In Jail

Posted by Rajesh Lal on March 30, 2010 – 8:30 pm
Ragknot has been imprisoned in a jail cell with no windows, he needs to tap out a message on the wall for Zaux in the other cell next to him to help plan their escape.
The problem is that he has to do it at exactly 9:15 PM, when the guard outside is switched, so the noise won’t be noticed. He can’t hear the switching of the guards through the walls, and he has no clock.
There is a faucet with water dripping very consistently from it in the corner, he can just make out the chiming of a church bell, but it chimes just once at the top of each hour, so he can’t tell the time from that. He can feel the wall facing west start to cool after the sun sets, but he doesn’t know what time the sun is setting, and this isn’t very precise in any case.
His dinner is always passed into your cell between 6:15 and 6:45. How does he determine when it is exactly 9:15 PM?

- Karl Sharman

This post is under “Tom” and has 2 respond so far.
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### 2 Responds so far- Add one»

1. 1. Elmelinda Said：

if dinner is close to 7pm, then wait for the 7pm church bell, count the drops till the next bell at 8. then divide the counts into 4. When the bell chimes at 9 count the divided number, poof the guards gone u start tappen and there you goooo….

2. 2. Stefan Said：

When dinner is served, the next time the church bell rings is at exactly 7:00PM. Count every 4th drip from the faucet until the next church bell [8:00PM]. Then at the ring from the church bell after 8:00PM [9:00PM] count every drop [NOT EVERY 4TH DROP] until you have counted all the drops that you counted from 7-8PM. The guard will be gone.

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