Wednesday, February 27, 2008

Scribe Post

Hi Everyone! Sorry for it being late! The first part of class in the morning we went over our homework from last night. After that we had a warm up to our next topic in Probability “The Fundamental Principal of Counting.”

Warm Up….
Question # 1
Find the probability of flipping three pennies and getting at lest 1 heads.

The first penny would be either heads or tails; the second would be also heads or tails etc. The chance of getting either one on any of the pennies on the three times would be ½., because there are 2 sides to a penny.

*Remember to watch how the question is worded.
Ex. 1. Heads AND Heads AND Heads mean multiplied.
2. Heads OR Heads mean add*

Question # 2

How Many Ways

A.) The café special for lunch offers a choice between two main courses (hamburger or chicken burger) and three different drinks. The “meal deal” allow you to pick one each. How many different “meal deal” are there?
*2 meals times the # of meal deals = 6 diff. ways.

B.) What if they decide to throw in a choice of fries, spicy fries or plain chips. How many “meal deals” are there now?
*Now you add the fries, spicy fries & plain chips on.

*Now you just add the 3 more diff meals to the first two. Witch now = to 18 diff. ways.

Now this is what the warm ups got us warmed up for…….

“The Fundamental Principal of Counting”

If there are M ways to do a first thing & N ways to do second thing then there are M * N ways to do both things.

Ex. Any one of 4 ties can be matched with any one of 3 shirts, how many shirts & ties combinations are possible?
* 4 ties times 3 shirts = 12 diff. ways to find combinations.

What if there are also 2 different pairs of pants that can be matched with all the shirts and ties, how many different “outfits are there now?

Now you try……

1.) How many 4 digit #’s are there if the same digit CANNOT be used twice?

* The First # can’t start with 0.

2.) How many 4 digit #’s are there if the same CAN be repeated?

* The same rule applies here can’t start with 0.

3.) How many 4 digit EVEN # CANNOT be used twice?

Well I think that is about it….I hope you guys/ gal’s understand what I wrote. The next scribe is…….Mercee

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