Please help! Algebra 2?! Probability....
Favorites|Homepage
Subscriptions | sitemap
HOME > > Please help! Algebra 2?! Probability....

Please help! Algebra 2?! Probability....

[From: ] [author: ] [Date: 12-03-10] [Hit: ]
+ 15C15 = 32192...but theres also ANOTHER way of doing it.the second way is shorter. and for the TOTAL someone got (2^15)=32768.......
An icecream vendor sells 15 flavors of icecream. You want to sample AT LEAST 4 of the flavors. How many different combos of ice cream flavors can you sample?

I know you can add 15C4 + 15C5 + ... + 15C15 = 32192...

but there's also ANOTHER way of doing it. which is the "TOTAL - (the ones NOT 4)"
For ex: TOTAL - (15C0 + 15C1 + 15C2 + 15C3) = 32192

the second way is shorter. and for the "TOTAL" someone got (2^15)=32768.

My question is HOW did they get "(2^15)"...? i know "15" is from the total flavors... but is "2" from either "YES" trying it and "NO" to trying it???

PLEASEEE EXPLAINN!! thank you!!

-
You got the reasoning right, but I think you just could not justify it ....
Imagine all 15 flavors in a line, and you can asign a 'yes' or 'no'
label for each to make your selections .... that will permit any
combination from zero to all 15 flavors selected. Since all the 15
need to be asigned a yes or no, it is 2^15 possibilities.

Then, you just need to subtract the following ....

==> 15C0 = 1
==> 15C1 = 15
==> 15C2 = 105
==> 15C3 = 455

==> 2^15 - (1 + 15 + 105 + 455) = 32192 .... answer
1
keywords: help,Algebra,Please,Probability,Please help! Algebra 2?! Probability....
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .