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A-Math P & C Qn!


The no. of applicants for a job is 15. (i)Calculate the no. of ways in which 6 applicants can be selceted for the interview.

The six selected applicants on a particular day. (ii)Caluculate the no. of ways in which the order of the six interviews can be arranged.

Of the 6 applicants, 3 have backgrounds in business, 2 have backgrounds in education and 1 has a background in recreation. Calculate the number of ways in which the order of the 6 interviews can be arranged, when applicants having the same background are interviewed in succesion.

Who's up for this challenge?

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Of the 6 applicants, 3 have backgrounds in business, 2 have backgrounds in education and 1 has a background in recreation. Calculate the number of ways in which the order of the 6 interviews can be arranged, when applicants having the same background are interviewed in succesion.

BBB EE RSo there are 3 groups of people and there are 3! ways of arranging these 3 groups
Within BBB group, there are 3! ways of arrange these 3 B people, similar within EE group, there are 2! ways of arrange these 2E people
so Total = Arrange Big Groups * Arrange within each group = 3! * 3! * 2!

Ai Ling Ong

Hi, I'm Ai Ling Ong. I enjoy coaching students who have challenges with understanding and scoring in 'O' Level A-Maths and E-Maths. I develop Math strategies, sometimes ridiculous ideas to help students in understanding abstract concepts the fast and memorable way. I write this blog to share with you the stuff I teach in my class, the common mistakes my students made, the 'way' to think, analyze... If you have found this blog post useful, please share it with your friends. I will really appreciate it! :)

Filed Under: A-Maths Tuition Tagged With: Exam Questions, p&c, Tips

Reader Interactions

Comments

  1. lijun(: says

    September 21, 2007 at 8:07 pm

    hey..

    my amaths really isn't strong, so i hope you'll help me and correct my mistakes. thanks.

    anyway. here are my answers:

    (i)no. of ways in which 6 applicants can be selceted for the interview = 15C6 = 5005

    (ii)no. of ways in which the order of the six interviews can be arranged = 6! = 720

    number of ways in which the order of the 6 interviews can be arranged, when applicants having the same background are interviewed in succesion = 3!X2!X3! = 72

    i'm quite doubtful of the last answer. haha. but i decided to try anyway. (:

  2. alwaysLovely says

    September 21, 2007 at 8:40 pm

    well done!
    Good job!

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