The number of ways in which a cricket team of 11 players can be chosen out of a batch of 15 players so that the captain of the team is always included, is
1001
Let's break down the problem of selecting a cricket team of 11 players from a batch of 15 players, with the specific condition that the captain must always be included in the team.
We need to form a team of 11 players. We have 15 players available in total. A key condition is that one specific player, the captain, is automatically selected for the team.
Since the captain is already included in the team of 11, we effectively need to choose the remaining players for the team from the rest of the available batch.
Because the captain is already chosen, we need to select fewer players from a smaller pool of players.
So, the problem simplifies to choosing 10 players from the remaining 14 players.
The number of ways to choose 10 players from 14 players is a combination problem, as the order in which the players are selected does not matter. We use the combination formula:
\(\binom{n}{k} = \frac{n!}{k!(n-k)!}\)
Where:
Substituting the values into the formula:
\(\binom{14}{10} = \frac{14!}{10!(14-10)!}\)
\(\binom{14}{10} = \frac{14!}{10!4!}\)
Let's expand the factorials and simplify:
\(\frac{14 \times 13 \times 12 \times 11 \times 10!}{10! \times 4 \times 3 \times 2 \times 1}\)
Cancel out \(10!\) from the numerator and denominator:
\(\frac{14 \times 13 \times 12 \times 11}{4 \times 3 \times 2 \times 1}\)
Simplify the denominator: \(4 \times 3 \times 2 \times 1 = 24\)
\(\frac{14 \times 13 \times 12 \times 11}{24}\)
Simplify by dividing 12 by 24:
\(\frac{14 \times 13 \times (12/12) \times 11}{(24/12)} = \frac{14 \times 13 \times 1 \times 11}{2}\)
Now, divide 14 by 2:
\(\frac{(14/2) \times 13 \times 11}{1} = 7 \times 13 \times 11\)
Calculate the product:
\(7 \times 13 = 91\)
\(91 \times 11 = 1001\)
The number of ways to choose the remaining 10 players from 14 is 1001.
Since the captain is always included, every combination of these 10 players with the captain forms a unique valid team of 11. Therefore, the total number of ways to choose the team with the captain always included is 1001.
| Total players available | 15 |
| Team size needed | 11 |
| Captain must be included | 1 |
| Remaining players to choose | 11 - 1 = 10 |
| Remaining players available | 15 - 1 = 14 |
| Calculation | \(\binom{14}{10}\) |
| Result | 1001 |
| Concept | Description | Formula |
|---|---|---|
| Combinations | Selecting items from a set where the order of selection does not matter. | \(\binom{n}{k} = \frac{n!}{k!(n-k)!}\) |
| Permutations | Arranging items from a set where the order of selection matters. | \(P(n, k) = \frac{n!}{(n-k)!}\) |
| Factorial | The product of all positive integers up to a given integer \(n\). | \(n! = n \times (n-1) \times \dots \times 1\) |
Combinatorics is a branch of mathematics concerned with counting, arrangement, and combination. Problems like selecting teams, forming batting orders, or scheduling tournaments in sports often involve combinatorics.
In this specific problem, because the captain's position is fixed and we are just selecting the remaining members to fill the team spots without considering their specific roles within the team (other than being a player), it's a straightforward combination problem.
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