In how many ways can a football team of 11 players be selected from 16 players? How many of these will (i) include 2 particular players? (ii) exclude 2 particular players.
Given that we need to choose 11 players for a team out of available 16 players,
Let us assume the choosing the no. of ways be N,
⇒ N = choosing 11 players out of 16 players
⇒ N = 16C11
We know that
And also n! = (n)(n – 1)(n – 2)…………2.1
⇒
⇒
⇒
⇒ N = 4368 ways
(i) It is told that two players are always included.
It is similar to selecting 9 players out of the remaining 14 players as 2 players are already selected.
Let us assume the choosing the no. of ways be N1,
⇒ N1 = choosing 9 players out of 14 players
⇒ N1 = 14C9
We know that
And also n! = (n)(n – 1)(n – 2)…………2.1
⇒
⇒
⇒
⇒ N1 = 2002 ways
(ii) It is told that two players are always excluded.
It is similar to selecting 11 players out of the remaining 14 players as 2 players are already removed.
Let us assume the choosing the no. of ways be N2,
⇒ N2 = choosing 11 players out of 14 players
⇒ N2 = 14C11
We know that
And also n! = (n)(n – 1)(n – 2)…………2.1
⇒
⇒
⇒
⇒ N2 = 364 ways
∴ The required no. of ways are 4368, 2002, 364.