perplexus.info :: Probability : Throwing needles

Throwing needles (Posted on 2005-01-19)

If I throw 1000 10-centimeter-long needles on to a tiled floor, where each tile is a 10 cm x 30 cm rectangle, approximately how many needles will end up lying across a crack?

You may assume that the widths of both the needles and the cracks are negligible.

Submitted by Sam

Rating: 3.6667 (3 votes)

Solution: (Hide)

You'd expect to find about 743 needles crossing the crack.
For a full explanation of why, see Charlie's post here

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Answer	K Sengupta	2008-04-14 16:31:57
re(4): Simulation supports	Charlie	2005-01-21 19:45:40
re(3): Simulation supports	Hugo	2005-01-21 19:35:00
re(2): Simulation supports	Charlie	2005-01-21 16:38:07
re: Simulation supports	Hugo	2005-01-21 15:20:36
Simulation supports "second thoughts"	Charlie	2005-01-21 14:57:14
re: solution -- second thoughts	Charlie	2005-01-20 13:51:09
re: solution	Steve Herman	2005-01-20 12:41:42
solution	Charlie	2005-01-19 14:29:05

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