All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Probability
Distinct Digit Determination (Posted on 2010-10-31) Difficulty: 3 of 5
M is an 8-digit base ten positive integer of the form abcdefgh, where each of the small letters represent a different digit from 1 to 9, and N is a base ten positive real number, such that M hectares is equal to N international acres.

For a value of M drawn at random between 12345678 (base ten) and 98765432 (base ten) inclusively, determine the probability that [N] contains precisely two distinct digits.

Bonus Question:

What is the answer to the original question, if M hectares is equal to N United States survey acres?

Notes:

(i) 1 international acre is equal to 0.40468564224 hectare.

(ii) 1 United States survey acre is equal to 0.404687261 hectare.

(iii)[N] denotes the greatest integer ≤ N, and [N] cannot contain any leading zero.

  Submitted by K Sengupta    
Rating: 5.0000 (1 votes)
Solution: (Hide)
(A) The required probability is ~= 0.0000661375661376, or 0.00661375661376 %, or 1/15,120.

(B) The required probability is ~= 0.0000909391534392 or 0.00909391534392 % or 1/10996.3636363636....

For an explanation, refer to the solution submitted by Charlie in this location.
Also, refer to his rejoinder in this location.

Comments: ( You must be logged in to post comments.)
  Subject Author Date
re: computer solution -- compared to random digitsCharlie2010-10-31 14:44:13
Solutioncomputer solutionCharlie2010-10-31 14:25:51
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information