February 14, 2014

Permutation and Combinations
Hi Guys! Mydee here, I hope you all had a wonderful long weekend. Last Friday we did examples using both permutation and combinations on the last pages of the booklet. (Sorry for posting late.)

Reminder:
February 18 (Tuesday) - Assignment Hand-In
February 21 (Friday) - Unit Test (Good Luck)

2C2 -> Two people are selected together, 11C5 -> remaining members to be on the committee

In Group A, 5 members can be selected from 20 students, In Group B, 8 members can be selected from the remaining 15 students ( 20-5=15), and the remaining 7 students will be part of Group C.

This question is a permutation, the dash method is used. *Don't forget to divide it by 2 because there is 2 repetition of E's.

• Since there are 2E in the word TEACHER and we are creating a 4 letter word, multiple steps are needed to find the answers for this question. 
• For the first 4 letter word,  2E's can be used but remember to permute it by mutlipying 4!, since we are only using 4 letters from a 7 letter word and divide by 2 since there are repetition.
•  For the second 4 letter word, only 1E will be used. 2C1 => means that one out of the two E's will be used. 1C1 => automatically means that there is only 1E . We don't have to divide it since there is no repetition and because only one E is used. 
• For the third letter word, there will be no E. FOr this one we could just write it as, 5C4, which means that we are choosing 4 letters out of the 5 letters. 
• For the last step, add up all the answers from the previous equations.

Mr. P gave these examples last Friday at the end of the class. 

~ In the first example, FEBRUARY has 2 R's and that is why we have to divide it by 2! at the end. We need to create a 4 letter word, 2C2 => 2 out of the 2 R's are used. 6C2 => selecting 2 more letters out of six letters to create the 4 letter word. Multiply by 4! to permute and then divide by 2! because of R repetition. 

 ~ For the second one, only one out of the two R's will be used. Two methods can be use. 

-  1C1 => this automatically means that you will only used 1 out of the 2 R's,   

-  2C1 => means you are choosing only 1 out of 2 R, this can also be used, but remember to divide it by 2! since are repetition. 

Example # 2: Create 4 letters word using the word "EVERYONE". 

The first method is the same as the one above. The second one is Mr. P's method.

~ We all know that 3C3, 2C2 and 1C1 is equals to 1 and so we don't really need to put it. But DON'T FORGET TO PERMUTE it to the number of letter using and to DIVIDE BY THE NUMBER OF THE REPETITION.

Reminder: If you use this method, make sure that you understand the equation that you are using and that you got the number right. 

Example #3: Create 5 letters word using the word "NOTEBOOK".
~For any of the examples above any method from the above can be used. Use the method that you are most comfortable with and make sure that you understand the steps on how and why the number in each equations are used. 


AND THAT'S ALL FOLKS!! WE ARE NOW DONE WITH UNIT ONE!!! YEHHEEYYY!!?!? THAT MEANS 7 UNITS LEFT! ;)