# We wish to select 6 persons from 8, but if the person A is chosen, then B must be chosen. In how many ways can the selection be made?

Given that we need to select 6 persons out of 8 persons, it is also mentioned that person B must be selected in the case of selection of A.

We need to find the no. of ways of selecting 6 persons.

The possible cases for the selection of 6 persons are:

i. selecting person A and person B and 4 others(similar to selecting 4 persons out of remaining 6 persons).

ii. selecting 6 persons other than person A and person B

Let us assume the no. of ways of selection be N.

N = (Selecting 4 persons from remaining 6 persons) + (Selecting 6 persons leaving Person A and B)

N = (6C4) + (6C6)

We know that ,

And also n! = (n)(n – 1)......2.1

N = 15 + 1

N = 16

The no. of ways of selecting 6 persons is 16.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Permutations & Combinations | Analyze your learningFREE Class
Challenging Quiz on P&C | Test Yourself55 mins
Check Your progress Part 2| Interactive Quiz: Permutation & Combination54 mins
Understand Permutations like never before60 mins
Interactive Quiz on Combinations50 mins
Lecture on Combinations49 mins
Interactive Quiz on Division and distribution of objects17 mins
Division and distribution of objects58 mins
Interactive Quiz on Combinations-0253 mins
Circular permutations61 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses