perplexus.info :: Probability : Mountain Motif

Mountain Motif (Posted on 2010-04-07)

A five digit positive integer is a mountain number if the first three digits are in strictly ascending order and the last three digits are in strictly descending order. For example, 46872 is a mountain number, but none of 43434, 54456 and 46766 is a mountain number.

Determine the probability that N is a mountain number, given that N is a positive integer chosen at random between 40000 and 99999 inclusively.

See The Solution Submitted by K Sengupta

Rating: 3.5000 (2 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re(2): my way

| Comment 5 of 8 |

(In reply to re: my way by Charlie)

I find your reaction swift and the solution comprehensive

Chapeau!

Posted by Ady TZIDON on 2010-04-08 13:05:31

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