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

Home > Probability
Picking cards (Posted on 2006-08-17) Difficulty: 3 of 5
A player picks random cards from an ordinary card deck, without returning them to the deck. How many cards should he pick so as to get at least one ace with 70% probability?

No Solution Yet Submitted by atheron    
Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Solution | Comment 5 of 8 |

The first card is drawn with a 1/13 or aprox. 7.69% chance of Ace.

The secound card compound with the first yelds an aprox. 15.53%.

The third an aprox. 23.5%

The fourth an aprox. 31.7%

The fifth an aprox. 40.0%

The sixth an aprox. 48.5%

The seventh an aprox. 57.2%

The eighth an aprox. 66.1%

The nineth an aprox. 75.2% So it would take nine cards


  Posted by Luna on 2006-08-18 17:01:00
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 (12)
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