NCERT Class 11-Math's: Chapter –7 Permutations and Combinations Part 7

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Question 23:

In how many ways can a football team of 11 players be selected from 16 players?

How many of them will

(i) Include 2 particular players?

(ii) Exclude 2 particular players?

Answer:

(i) (ii)

Question 24:

A sports team of 11 students is to be constituted, choosing at least 5 from Class XI and atleast 5 from Class XII. If there are 20 students in each of these classes, in how many ways can the team be constituted?

Answer:

Question 25:

A group consists of girls and boys. In how many ways can a team of 5 members be selected if the team has

(i) No girls

(ii) At least one boy and one girl

(iii) At least three girls.

Answer

(i)

(ii)

(iii)

Objective Type Questions

Choose the correct answer out of the given four options against each of the Exercises from 26 to 40 (M.C.Q.).

Question 26:

If then n is equal to

(A) 20

(B) 12

(C) 6

(D) 30

Answer: (A)

Question 27:

The number of possible outcomes when a coin is tossed 6 times is

(A) 36

(B) 64

(C) 12

(D) 32

Answer: (B)

Question 28:

The number of different four digit numbers that can be formed with the digits and using each digit only once is

(A)

(B)

(C)

(D)

Answer: (C)

Question 29:

The sum of the digits in unit place of all the numbers formed with the help of 3, 4, 5 and 6 taken all at a time is

(A)

(B)

(C)

(D)

Answer: (B)

Question 30:

Total number of words formed by 2 vowels and 3 consonants taken from 4 vowels and 5 consonants is equal to

(A)

(B)

(C)

(D)

Answer: (C)

Question 31:

A five digit number divisible by 3 is to be formed using the numbers 0, 1, 2, 3, 4 and 5 without repetitions. The total number of ways this can be done is

(A)

(B)

(C)

(D)

[Hint: 5 digit numbers can be formed using digits or by using digits since sum of digits in these cases is divisible by 3.]

Answer: (A)

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