If a Caterpillar climbes up an 18 foot telephonepole... 3 feet during the day, but falls back down 2 feet at night... How many days does it take him to reach the top?
2007-09-30 14:11:57 · 2 answers · asked by Kelly S 1 in Science & Mathematics ➔ Earth Sciences & Geology
Slightly tricky. The caterpillar makes net progress of 1 foot every 24 hours (one day). On day 14 it reaches the 17 foot mark, at night slides back down to 15 feet. On day 15 it climbs 3 feet to the top. So the answer is 15 days. Most people look at it very quickly and answer, "18 days."
2007-09-30 14:28:47 · answer #1 · answered by Howard H 7 · 1⤊ 1⤋
This one catches a lot of people. You want to say that every day, he goes a total of one foot (+3-2), which would give you 18 days. But remember, once his +3 ft puts him at the top, he doesn't have to slip back down any more.
Figure the correct answer like this. How many days would it take him to end up 3 ft below the top at the end of the night? Add one more day to that (he climbs 3 ft and reaches the top).
The answer is: 16 days
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Howard, on day 14 he only hits 16 ft, then slips back down to 14 ft. You've given him an extra foot somewhere in there.
2007-09-30 14:28:58 · answer #2 · answered by skeptik 7 · 1⤊ 1⤋