Maths puzzle
Okay, here's one to get your brain in knots. I spent a while trying to prove that it was impossible only to find out that it's not; it's just a little devious instead.
Four people have to cross a bridge. The bridge can only support two people and they each walk at different speeds, it takes them 1,2,5,10 mins respectively to cross. The problem is that it's dark and there's only one torch. So, one person has to bring the torch back so the next two can cross. (I.e. two go over, one comes back; repeat until everyone's over.)
Make sense? I hope so...
The hard part is this: you only have 17 mins to get everyone over the bridge. Good luck! (Answers on a postcard, please.)
Thanks Matt.
1 Comments:
Done it!!!
[1] and [2] cross (2 mins passed)
[2] brings torch back (4 mins passed)
[5] and [10] cross (14 mins passed)
[1] brings torch back (15 mins passed)
[1] and [2] cross (17 mins passed)
:-)
Post a Comment
<< Home