Test

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2/25

• 7.4
• 8.1
• Test
• Homework
• Book Assignment 7
• Section 7.4, p. 488 - 2, 8(order doesnt
  matter), 13

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7.4
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Lets see how much we remember from Monday

• A state wants to create license plates that have
  two letters followed by two numbers. How many
  different plates can they make?

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• The German club has 12 members. In how many
  different ways the club elect a President and VP?

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4. Permutations

• We refer to the number of different subsets of
  size r that we can make from a set of size n as
  the number of permutations of n things taken r at
  a time.
• The shorthand is nPr

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5. What happens if were going to send 2 people
to the math tournament from the 6 members of the
math club?

• In this case 1,2 is the same as 2,1, where as
  they were different in the previous example.
• We are now dealing with combinations.
• For example, if abc and bac are considered
  different. We have permutations. If they are the
  same, we have combinations.
• The number of combinations of n things taken r at
  a time is nCr.

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• We had that 6P230. Will 6C2 be more or less?
  Why?

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We can be systematic

• 12 23 34 45 56
• 13 24 35 46
• 14 25 36
• 15 26
• 16
• 5432115
• Does it make sense that we have half as much?

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What happens if we send 3 people?

• 123 134 145 156
• 124 135 146
• 125 136
• 126
• 234 245 256
• 235 246
• 236
• 345 356
• 346
• 456

6P3 20
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So we have that
We know that 15 is half of 30. What kind of
relationship do 120 and 20 have?
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For the AZ Powerball, you first pick 5 different
regular numbers from the numbers 1-55.

• How many different Powerball combinations are
  there?

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8.1 GEOMETRY!!!
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1. Some facts

• Geometry-literally means to measure the earth.
• People have been using for years.
• We see in nature a lot.
• Important name Euclid-The Elements, written in
  300 B.C. and used until the 19th cent. As a HS
  text.

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2. Geometry is fun!!

• Tetris
• Art
• Optical Illusions.

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Where do we see/use geometry?
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3. Basic Terms and Ideas

• How many lines can we make through one point?
• How many lines can we make through two points?
• How many lines can we make through three points?

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Exam

• Mean 81 Median 87
• On your exam I put your exam score and a really
  rough estimate of your grade. The homework etc
  might pull you up of down.
• Please look over your exam before asking me
  questions. I will only discuss failings in my
  adding right now.
• Plan on seeing me if you didnt do so well. This
  is YOUR responsibility.

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1.

• Meant to find a general formula, like you did in
  the homework, not just say add 3.

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4.

• Where is the majority of the data?

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6b.

• Why do we multiply 3/12 and 2/11?

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If we have time

• 3 things I (Ms Leahy) am doing well.
• 3 things I (Ms Leahy) can do better.