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        riddles >> easy >> CLIMBING SNAIL
        
(Message started by: eviljed on Aug 7^th, 2002, 8:39am)

Title: CLIMBING SNAIL
Post by eviljed on Aug 7^th, 2002, 8:39am

A snail is at the bottom of a well that is 20 meters in depth. Every day the snail climbs 5 meters upwards, but at night it slides 4 meters back downwards. How many days must elapse till the snail reaches the top of the well?

After the first day, he will net 1 meter in height, after the second, 2, and so on.

On the 15th day, he will start at 14 meters , climb 5 to 19, the slide back down to 15.

On the 16th day, he will climb from 15 to 20, but not slide down because he is out.

16 Days.

Title: Re: CLIMBING SNAIL
Post by SingGloryHallejuah on Mar 31^st, 2004, 2:32pm

How did the snail get at the bottom of the well to begin with? ;)

Title: Re: CLIMBING SNAIL
Post by rmsgrey on Apr 1^st, 2004, 6:46am

He climbed down the opposite side at the rate of 5 meters per day - since he didn't have a slime trail to slide down he didn't slide noticeably each night...

Of course, a diurnal snail isn't all that common - they tend to move around at night when they have less tendency to dry out...

Title: Re: CLIMBING SNAIL
Post by pzld on Oct 12^th, 2004, 3:29pm

Day 1 elapsed; he was at 1 meter.
...
day 14 elapsed; he was at 14meters.

day 15 did not elapse; he made to the top.

Answer; 14 days elapsed.

Title: Re: CLIMBING SNAIL
Post by Icarus on Oct 12^th, 2004, 5:15pm

Read eviljed's answer. At nightfall on the 15th day, the snail has only reached 19 meters, so it is still trapped. It is only at nightfall on the 16th day that the snail makes it to the top. Since it required the entire day to climb to the top, the 16th day has also elapsed (though the following night is not included).