Home
Class 11
MATHS
(i) In how many ways a committee of 4 me...

(i) In how many ways a committee of 4 members out of 5 gents and 6 ladies can be formed if there is at least one lady in the committee?
(ii) From a class of 12 boys and 8 girls, 10 students are to be chosen for a competition, including at least 4 boys and 4 girls. The two boys who won the prizes last year should be included. In how many was can this selection be made?

Text Solution

AI Generated Solution

The correct Answer is:
### Step-by-Step Solution #### Part (i) **Problem Statement:** In how many ways can a committee of 4 members be formed from 5 gents and 6 ladies if there is at least one lady in the committee? 1. **Identify the Total Members:** - Gents = 5 - Ladies = 6 - Total members = 5 + 6 = 11 2. **Calculate Total Ways to Form a Committee of 4:** - The total ways to form a committee of 4 members from 11 people (5 gents + 6 ladies) is given by the combination formula: \[ \text{Total ways} = \binom{11}{4} \] - Calculate: \[ \binom{11}{4} = \frac{11 \times 10 \times 9 \times 8}{4 \times 3 \times 2 \times 1} = 330 \] 3. **Calculate Ways with No Ladies (All Gents):** - The number of ways to select 4 gents from 5: \[ \text{Ways with no ladies} = \binom{5}{4} = 5 \] 4. **Calculate Ways with At Least One Lady:** - To find the number of ways with at least one lady, subtract the ways with no ladies from the total ways: \[ \text{Ways with at least one lady} = \text{Total ways} - \text{Ways with no ladies} = 330 - 5 = 325 \] 5. **Final Answer for Part (i):** - The number of ways to form a committee of 4 members with at least one lady is **325**. --- #### Part (ii) **Problem Statement:** From a class of 12 boys and 8 girls, 10 students are to be chosen for a competition, including at least 4 boys and 4 girls. The two boys who won the prizes last year should be included. In how many ways can this selection be made? 1. **Identify Fixed Members:** - 2 boys (who won last year) are already included. Thus, we need to select 8 more students. 2. **Determine Remaining Students:** - Remaining boys = 12 - 2 = 10 - Girls = 8 3. **Possible Cases for Selection:** - We need to consider cases based on the number of boys and girls selected, ensuring at least 4 boys and 4 girls: - **Case 1:** 2 additional boys and 6 girls - **Case 2:** 3 additional boys and 5 girls - **Case 3:** 4 additional boys and 4 girls 4. **Calculate Each Case:** - **Case 1:** 2 boys and 6 girls \[ \text{Ways} = \binom{10}{2} \times \binom{8}{6} = 45 \times 28 = 1260 \] - **Case 2:** 3 boys and 5 girls \[ \text{Ways} = \binom{10}{3} \times \binom{8}{5} = 120 \times 56 = 6720 \] - **Case 3:** 4 boys and 4 girls \[ \text{Ways} = \binom{10}{4} \times \binom{8}{4} = 210 \times 70 = 14700 \] 5. **Total Ways:** - Add the number of ways from all cases: \[ \text{Total ways} = 1260 + 6720 + 14700 = 22680 \] 6. **Final Answer for Part (ii):** - The total number of ways to select the students for the competition is **22680**. ---
Promotional Banner

Topper's Solved these Questions

  • PERMUTATION AND COMBINATION

    NAGEEN PRAKASHAN ENGLISH|Exercise Exercise H|10 Videos
  • PERMUTATION AND COMBINATION

    NAGEEN PRAKASHAN ENGLISH|Exercise Exercise I|10 Videos
  • PERMUTATION AND COMBINATION

    NAGEEN PRAKASHAN ENGLISH|Exercise Exercise F|27 Videos
  • MATHEMATICAL REASONING

    NAGEEN PRAKASHAN ENGLISH|Exercise Misellaneous exercise|7 Videos
  • PRINCIPLE OF MATHEMATICAL INDUCTION

    NAGEEN PRAKASHAN ENGLISH|Exercise Exercise 4.1|1 Videos

Similar Questions

Explore conceptually related problems

From a class of 12 boys and 10 girls, 10 students are to be chosen for a competition; at leastincluding 4 boys and 4 girls. The 2 girls who won the prizes last year should be included. In how many ways can the selection be made?

From a class of 12 girls and 15 boys, 12 students are to be chosen for a competition including 7 boys and 5 girls. The two girls and 3 boys who won the prizes last year should be included . In how many ways can the selection be made ?

In how many ways can a committee of 8 be chosen from 10 individuals?

In how many ways can a committee of 6 members e formed out of 4 teachers and 7 students when (i) one teacher is in the committee? (ii) at least one teacher is in the committee?

Find the number of ways in which a committee of 6 members can be formed out of 4 officers and 8 jawans, if there are at least 2 officer in the committee.

Find the number of ways in which a committee of 11 members can be formed out of 6 teachers and 8 students if there are at least 4 teachers in the committee.

Out of 5 men and 2 women, a committee of 3 is to be formed. In how many ways can it be formed if at least one woman is to be included?

A committee of 7 members has to be formed from 9 boys and 4 girls. In how many ways can this be done when the committee consists of at least 3 girls

From 6 boys and 7 girls a committee of 5 is to be formed so as to include at least one girl. Find the number of ways in which this can be done.

A committee of 7 members has to be formed from 9 boys and 4 girls. In how many ways can this be done when the committee consists of exactly 3 girls

NAGEEN PRAKASHAN ENGLISH-PERMUTATION AND COMBINATION -Exercise G
  1. There are 4 girls and 7 boys in a group. In how many waysa team of 5 m...

    Text Solution

    |

  2. There are 8 questions in a paper and a student have to attempt 5 quest...

    Text Solution

    |

  3. (i) In how many ways a committee of 4 members out of 5 gents and 6 lad...

    Text Solution

    |

  4. Out of 20 consonants and 5 vowels, how many words can be formed contai...

    Text Solution

    |

  5. Out of 12 consonants and 5 vowels, how many words of 2 consonants and ...

    Text Solution

    |

  6. How many words can be formed with 3 vowels and 2 consonants taken from...

    Text Solution

    |

  7. There are 10 points on a plane of which 5 points are collinear. Also, ...

    Text Solution

    |

  8. There are 16 points in a plane of which 6 points are collinear and no ...

    Text Solution

    |

  9. No. of diagonals of a hexagon are:

    Text Solution

    |

  10. Find the number of diagonals of a 16-sided polygon.

    Text Solution

    |

  11. (i) Find the number of sides of a polygon if it has 35 diagonals. (i...

    Text Solution

    |

  12. In how many ways can 7 red and 6 black balls be arranged in a row, if ...

    Text Solution

    |

  13. In how many ways can 12 white and 8 black balls be arranged in a row i...

    Text Solution

    |

  14. A person invites a group of 10 friends at dinner and seats (i) 5 on ...

    Text Solution

    |

  15. In an examination a minimum is to be secured in ech of 5 subjects for ...

    Text Solution

    |

  16. It is necessary to pass in each subject out of 7 subjects in an examin...

    Text Solution

    |

  17. Find the number of ways of getting 2 heads and 4 tails in 6 throws of ...

    Text Solution

    |

  18. How many factors are there of the number 2520?

    Text Solution

    |

  19. How may other factors are there of the number 37800?

    Text Solution

    |

  20. Out of 4 mangoes, 5 bananas and 6 guava, find (i) number of ways in ...

    Text Solution

    |