Get Answers to all your Questions

header-bg qa

In how many ways can Sheela form a musical team of 11 members from 20 head count such that 2 trained vocalists, 1 tabla player, 1 harmonium playerfrom them must always be included in the team?

Option: 1

\frac{16!}{7!11!}


Option: 2

\frac{16!}{7!9!}


Option: 3

\frac{18!}{7!11!}


Option: 4

\frac{20!}{7!9!}


Answers (1)

best_answer

Note the following:

  • The formula for the combination for the selection of the \mathrm{x} items from the \mathrm{y}different items is \mathrm{^{y}C_{x}=\frac{y!}{x!\left ( y-x \right )!}}

  • The restricted combination for the selection of the \mathrm{r} items from the \mathrm{n}different items with \mathrm{k} particular things always included is \mathrm{=^{n-k}C_{r-k}}

The number of team members who must always be present in the team is

=2+1+1

=4

Since 4 musical experts must always be included in the team, the following is evident.

  • The number from which the restricted combination is to be made is .

           \mathrm{n-k=20-4=16}

  • The number with which the restricted combination is to be made is

           \mathrm{r-k=11-4=7}

Therefore, the required restricted combination is

\mathrm{=^{n-k}C_{r-k}}

\mathrm{=^{16}C_{7}}

=\frac{16!}{7!9!}

Posted by

jitender.kumar

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE