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| Question 409103:  I have the the first part to this problem, I think. The tree diagram I have drawn but have no idea if it is correct.  I am completely stumped on the last 2 parts.  I have read and reread the material and even looked at how some of the problems are done on here. But I am still lost on this one.  PLEASE HELP! I have to turn it in this evening! Thanks...
 Problem:
 A mini license plate for a toy car must consist of a two letters followed by a one digit odd number. Each letter must be a P, Q or a R. Repetition of letters is not permitted.
 •	Use the counting principle to determine the number of points in the      sample space.
 •	Construct a tree diagram to represent this situation.
 •	List the sample space.
 •	Determine the exact probability of creating a mini license plate with a       Q. Give solution exactly in reduced fraction form.
 A) P,Q, and R = 3 ways  1 digit odd # = 5 ways
 3*5 = 15
 B) tree diagram
 1st column P, Q, R
 2nd column 1,3,5,7,9 beside each letter
 c) HELP!
 D) Help!
 
 Answer by jim_thompson5910(35256)
      (Show Source): 
You can put this solution on YOUR website! A) 
 # of letters possible * # of letters possible * # of odd digits
 
 = 3 * 2 * 5
 = 6 * 5
 = 30
 
 So there are 30 different license plates (you're missing half of them)
 
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 B)
 
 I can't draw here.
 
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 C)
 
 Sample Space
 
 {PQ1, PQ3, PQ5, PQ7, PQ9,
 PR1, PR3, PR5, PR7, PR9,
 QP1, QP3, QP5, QP7, QP9,
 QR1, QR3, QR5, QR7, QR9,
 RP1, RP3, RP5, RP7, RP9,
 RQ1, RQ3, RQ5, RQ7, RQ9}
 
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 D)
 
 There are 20 license plates that have a Q in them, and they are
 
 {PQ1, PQ3, PQ5, PQ7, PQ9,
 QP1, QP3, QP5, QP7, QP9,
 QR1, QR3, QR5, QR7, QR9,
 RQ1, RQ3, RQ5, RQ7, RQ9}
 
 There are 30 plates total. So the probability is
   
 
 If you need more help, email me at jim_thompson5910@hotmail.com
 
 Also, please consider visiting my website: http://www.freewebs.com/jimthompson5910/home.html and making a donation. Thank you
 
 Jim
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