Posted by Kennedy on Sunday, January 18, 2009 at 6:03pm.
A)If a license plate consists of 2 letters followed by 3 digits or 3 letters followed by 2 digits, how many license plates can be created?
B)You are given an exam with only 9 questions. if each question has 4 choices, howmany different possible answers can you have for the entire exam?
C)If you have 20 students in your class, how many different ways can a committee of 5 be chosen if 1 person on the committee will be the president?
E) 25 people run a marathon. The first 6 people to finish will receive an award for their finish position. How many ways can the awards be given?
F) How many distinct arrangements of the letters in the word UNUSUAL can be made?
G) How many 4 letter words can be fromed by slection four letters from the word UNIFORM?
i know that you use ncr and ncp, but i don't understand can someone please show work! thanks for your time yoo

MATH PLEASEEEEE  Damon, Sunday, January 18, 2009 at 6:27pm
I assume the letter and numbers can be repeated, for example AA111
In that case all slots are independent, you do not have to do combinations
If there are 26 letters (in practice you do not want to use them all because 0 and O look to much alike etc)
ways to get 2 letters = 26*26
ways to get 3 digits = 10*10*10 (using 09)
so 26*26*1000
you can do the second half

Math  Writeacher, Sunday, January 18, 2009 at 6:31pm
http://www.jiskha.com/display.cgi?id=1232319439
http://www.jiskha.com/display.cgi?id=1232305810

MATH PLEASEEEEE  Damon, Sunday, January 18, 2009 at 6:35pm
B is done the same as A, 4^9 (huge)
C Ignoring the president bit, how many combinations of 20 students taken 5 at a time?
C(n,r) = n!/[(r!(nr)! ]
= 20! / [5! (15!) ]
= 20*19*18*17 *16 /[5*4*3*2]
= 19 * 3* 17 * 16
now you have in each of these 4 groups of five students, five choices for president
so multiply that answer by 5*5*5*5
That is enough, you should be able to continue

MATH PLEASEEEEE  Damon, Sunday, January 18, 2009 at 6:42pm
E) 25 people run a marathon. The first 6 people to finish will receive an award for their finish position. How many ways can the awards be given?

Well E is different from D in that the order of the 6 people matters (one gets blue ribbon, one red ribbon etc) so it is not just a combination of 6 out of 25
but is called the "permutations" of 25 taken 6 at a time:
P(n,r) = n!/(nr)!
=25!/19! = 25*24 *....20

MATH PLEASEEEEE  Damon, Sunday, January 18, 2009 at 6:48pm
U N U S U A L
This would be permutations of 7 objects except that we have three identical Us.
so permutations of 7 objects = 7!
but we have embedded in there the permutations of three objects
3!
so I get
7!/3! = 7*6*5*4

MATH PLEASEEEEE  Kennedy, Sunday, January 18, 2009 at 9:57pm
thanks for your time and your help!
Answer This Question
Related Questions
 Computers  In Python  A state creates license plates, each containing two ...
 math check my work  a license plate has 2 letters followed by 4 digits.how many...
 math please check my work  a license plate has 2 letters followed by 4 digits....
 algebra  In Utah, a license plate consists of 3 digits followed by 3 letters. ...
 Math  A license plate is to consist of two letters followed by three digits. ...
 survey of math  A license plate is to consist of 2 letters followed by 3 digits...
 Math  A state creates license plates that each contain two letters followed by ...
 statistics  A license plate is to have 3 digits followed by 2 uppercase letters...
 College probability and statistics  The current license plates in New York ...
 Math  How do I work this problem? A license plate is to consist of 2 letters ...
More Related Questions