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

Home > Just Math
Inscribed circle and Line Choice (Posted on 2010-06-27) Difficulty: 3 of 5
(A) Out of 100 straight lines having respective lengths 1, 2, 3, ......, 99, 100; determine the total number of ways in which four straight lines may be chosen which will form a quadrilateral in which a circle may be inscribed.

(B) Out of 101 straight lines having respective lengths 1, 2, 3, ......, 99, 100, 101; determine the total number of ways in which four straight lines may be chosen which will form a quadrilateral in which a circle may be inscribed.

No Solution Yet Submitted by K Sengupta    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts re: start of analysis; computer finish (spoiler) | Comment 2 of 3 |
(In reply to start of analysis; computer finish (spoiler) by Charlie)

Just verifying:

The addition of 101th line causes additional 4-tuples from (1,2,100,101) to (98,99,100,101).

Simple count shows that we add (49,49,48,48,....1,1) new combinations.

49*50=2450  
so does  82075-79625=2450

Just verifying!


  Posted by Ady TZIDON on 2010-06-29 10:52:04
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 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information