Combinatorics Lesson 1 [sum rule and product rule]

Questions

  • 1

    problem related to video

    sachinmittal.mittal1@gmail.com
    Reply

    I am unable to see video . i can just hear audio . is there any issue with this video ? or its frm my side ?

  • 3

    Palindromes Problem

    Pavan55
    Reply

    Sir in palindroms problem Task 5,6,7 dependent on Task 1,2,3 respectively.then how can we apply here Product rule?

    • getgatebook

      What ever the way T1 is done if T2 has equal no of ways then we say tasks T1,T2 are independent.

    • getgatebook

      Here for every 26 ways of filling 1st position we have equal, that is one, no of ways of filling last position

    • Pavan55

      can we say that T7 is dependent on T1?

  • 2

    number of 5 digit integers possible @ 17:34

    khushbu_mevada
    Reply

    sir for 5 digit integers problem we should use 6 positions as 1st position for sign(negative or positive) and 2nd-6th for 5 digit number.
    in that way the ans will be 2x9x10^4.

    • khushbu_mevada

      this is related to 2nd lecture. by mistake added here.

    • getgatebook

      In the question I was discussing positive integers

  • 3

    problem(5 member committee) in combination

    gaurav27pro
    Reply

    sir according to product rule at 8:24 possblie solution would be 5*9*8*7*6 ie 5 for raju snd remaing 4 for other persons but sir according to the combination 5* 9C4=(9*8*7*6*5)/4! answer are different

    • getgatebook

      I understand your problem. Can you tell me for which problem you get these 2 solutions ?

    • sharmapro19

      @gaurav27pro Please elaborate your probem…

    • sharmapro19

      As it is 5 member committee . and by looking at your number of people are 10
      If raju sits at a fixed seat or position leaving other 4 seats or position for the remaining members then sitting of raju can be done only in 1 way i.e.
      answer should be (1*9*8*7*6) by product rule.
      And according to definition of combination you to select people first((9C4) and then arrange them(4!) later , assuming raju sits on a fixed position. Then total number of ways of committee forming is 1*( 9C4 * 4! ) which is equal to (1*9*8*7*6)

  • 1

    If the word "INDEPENDENCE " do all vowel occur together how can calculate total no of arrangement ?

    shibapro19
    Reply

    Sir , I can’t solve this question and my ans showing wrong .

    • getgatebook

      Please watch all the combinatorics lectures and then try to answer this question. After that if you can not answer this question then please post your question in the below forum. http://forum.thegatebook.in/

  • 1

    at time 18:53

    rajupro
    Reply

    4*9^3(4 mean fill 5 on 4 places )

  • 1

    @21:50

    shreyapro
    Reply

    Sir, C1(1,2,0) and C2(0,2,0). Sir there can be Case (1,1) when both rani and vani will go and when only vani will go(0,1). Sir,these two can be considered or not?

    • getgatebook

      yes, they are considered in the 3*3 possibilities.

  • 0

    link for combinatorics practise questions??

    shubhampro19
    Reply

    link for practising combinatorics question??