Interview Question 3787
Created by admin on Mon, 19/11/2012 - 13:13
Question:
A snail is at the bottom of a 20 meters deep pit. Every day the snail climbs 5 meters upwards, but at night it slides 4 meters back downwards. How many days does it take before the snail reaches the top of the pit?
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Answer:
On the first day, the snail reaches a height of 5 meters and slides down 4 meters at night, and thus ends at a height of 1 meter.
On the second day, he reaches 6 m., but slides back to 2 m.
On the third day, he reaches 7 m., and slides back to 3 m.
On the fifteenth day, he reaches 19 m., and slides back to 15 m.
On the sixteenth day, he reaches 20 m.
Conclusion: The snail reaches the top of the pit on the 16th day!.