School-Safe Puzzle Games

Frog stuck in a well

In the bottom of a well, 45 feet deep, there was a frog that started traveling toward the top. In his journey, he ascended 3 feet every day, but fell back 2 feet every night.

In how many days did he get out?

[submitted answers will show in about a day]

Couple months back, a similar math brain teaser was posted.

35 Comments to “Frog stuck in a well”


  1. Alexey | Guest

    43


  2. Mark W | Guest

    On the 43rd day the frog ascends from 42 ft. to 50 ft. so it is on the 43rd day that the frog reaches the top.


  3. Mark W | Guest

    aaah! I mean the frog ascends from 42 ft. to 45 ft. on the 43rd day!


  4. Justin | Guest

    I guess that as he makes net progress of 1 foot per day the answer would be 1 day per foot until he got within 3 feet of the top and then one day more fot the last 3 feet as he would be able to leave the well before slipping down the following night.


    With that in mind I make it 43 days in total.


  5. charity | Guest

    43 days


  6. jason | Guest

    43 days


  7. Daniel | Guest

    43 days


  8. Joe | Guest

    43 days?


  9. Shawn | Guest

    43 days


    On the 43rd day the frog jumped up 3 feet from his previous night’s height of 42 feet, and escaped the well.


    He might have escaped sooner, but Lassie only helps humans. Actually, collies are known for their particular disdain for amphibians at large.


  10. Sala | Guest

    The frog should ascend for 21 days to exit the 45-feet well.


  11. Scott K | Guest

    its gotta be something like 42. he climbs up 1 foot every day total but when he gets to 42 the 3 he climbs in the day will get him out and he wont need to climb anymore or fall back. 43 ill say, 42 to get to 42 and then 1 more day.


  12. ED | Guest

    42 days


  13. Jay | Guest

    I guess it depends… 43 days if the frog makes it to the edge of the well and climbs out or 44 days for it to pass the mark…


  14. Rasool | Guest

    43 days


  15. Robert L | Guest

    43 days to reach the top, but you know honestly unless frogs are a lot tougher than me I don’t think he ever made it. I mean he would have starved by then lol.


  16. John Lewis Highsmith | Guest

    43, unless he is stupid, and then it will be 44


  17. andi | Guest

    After 42 days, he’s up 42 feet. On the 43rd day, he ascends the 3 feet to the top.


  18. biobot | Guest

    41 days because on the 41st day he would clear the last two feet without slipping back down. (ie. he’d jump out of the well)


  19. keith | Guest

    43


  20. azri | Guest

    43


  21. Mike | Guest

    45 days… one foot each 24 hours


  22. milo zachary | Guest

    43 days. Every day he gained one foot, so he began each day at the level of the preceeding day’s number, so on day 42, he began at 41 feet, and climbed to 44 feet. On day 43, he began at 42 feet and climbed to 45 feet and was out.


  23. Ian mckinnon | Guest

    42


  24. Amie Krone | Guest

    I’m going to guess – 44 days.


  25. Megan W | Guest

    First of all, yes, I did have a lot of time on my hands…


    The graph illustrates progress made each day (in green) and lost each night (in red).
    I conclude that the frog takes 44 days to exit the well, because though the frog reaches 45 feet on day 43, this just means that he is at the top of the well… not beyond it.
    44 days. :)


  26. Megan W | Guest

    The image didn’t show in my previous comment, so the link is here if anyone could be bothered accessing it!
    http://a174.ac-images.myspacec.....2807d5.jpg


  27. RK | Profile


    Hi Megan- don’t think the graph made it?

    I believe the point you raise is similar to what Jay is saying, and is probably why Joe put a ‘?’ after his answer of 43 (and might explain John Highsmith’s comment and Amie’s answer of 44)

    Not sure what others think – while the ‘official’ answer is ’43′, in light of the way the question is worded- aren’t ’43′ & 44′ both acceptable?


  28. Ituri | Guest

    The frog will ascend 1 foot each day for 42 days and on the last day it’ll ascend 3 feet (because no night spent in the well on this day). Thus, the frog will exit the well on the 43rd day since beginning its climbing.


  29. Scott K | Guest

    what kind of rock is the well made out of, thats the real question.


  30. Angelo | Guest

    It took the frog 45 days to get out of the well. You subtract 3 feet from the original height (froggy going up) then add 2 after subtracting the original height from 3 (froggy going down).


  31. RK | Profile


    I suspect Shamrock Smiley


  32. Nir | Guest

    You are all wrong except for Amie and Megan.


    The correct answer is 44. I have programmed a flash simulator of this which you can try out yourselves, available on my website with the source code included.


    http://www.motion2.net/frog.html


    Enjoy :)


  33. Nir | Guest

    Oooops, my bad. I made a programming error, the correct answer is 43. Amie and Megan are wrong.


    See my simulation
    http://www.motion2.net/frog.html


    :)


  34. Hendy | Profile

    On the 43 day. The frog would be able to jump high enough to get out and would not need to fall back that night.


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