Posted by **Math** on Tuesday, May 15, 2007 at 2:11pm.

I had to solve for this:

1) choose 4 people from a class of 12

My answer:

n=12 r=4

12C4 = 495

2) chosse 8 people from a class of 12

my answer:

n=12

r=8

12C8 = 495

why is it that they both eqaul 495? maybe I am doing it wrong but I am confused why do they both equal 495?

They are the same, both 2 from the mean of 6. If you do 12C6, you get the max. A neat thing to do is to graph each possibilty,

12C1

12C2

12C3 and so on until

12C12.

Graph number combinations vs n.

If you smooth it up, you get the binomial approximation to the normal probability curve.

thanks bobpursley

to go along with what bobpursley showed you, try to finish this pattern

1

1 1

1 2 1

1 3 3 1

1 4 6 4 1

1 5 10 10 5 1

...

.

.

to get a new number, add the one immediately above and one to the left, the left column is made up of 1's

This is Pascal's Triangle. Look at the row that starts with 1 12 ...

Did you notice something?

## Answer This Question

## Related Questions

- Math - There are three times as many people in the psychology class as in the ...
- algebra PLEASE HELP ASAP - 1. the probability of a basketball player hitting a ...
- math plz help Irving - How many ways can 4 students be chosen from a class of 12...
- social studies 9 - using the data in table5-1, determine how large a part of ...
- Social studies - 12. The American Revolution most likely encouraged the Mexican ...
- Algebra - There are three times as many people in the psychology class as in the...
- math - ther 840 people in mrs mitchells class and 453 people in mrs coles class ...
- math - Mr. Smith’s first period class had an average of 90% on the first test, ...
- Math - A game show has three doors labelled A,B, and C behind which there may ...
- English - There are 7 classes for first year students. Each class is composed of...

More Related Questions