Discussion
Home ‣ Aptitude ‣ Permutation and Combination Comments
- Question
In how many ways can letter of the word RAILINGS arrange so that R and S always come together?
Options- A. 1260
- B. 2520
- C. 5040
- D. 1080
- Correct Answer
- 5040
ExplanationThe number of ways in which the letters of the word RAILINGS can be arranged such that R & S always come together is
Count R & S as only 1 space or letter so that RS or SR can be arranged => 7! x 2!
But in the word RAILINGS, I repeated for 2 times => 7! x 2!/2! = 7! ways = 5040 ways.
- 1. The letters of the word PROMISE are to be arranged so that three vowels should not come together. Find the number of ways of arrangements?
Options- A. 4320
- B. 4694
- C. 4957
- D. 4871 Discuss
- 2. In how many different ways can the letters of the word 'HAPPYHOLI' be arranged?
Options- A. 89,972
- B. 90,720
- C. 72,000
- D. 81,000 Discuss
- 3. From a total of six men and four ladies a committee of three is to be formed. If Mrs. X is not willing to join the committee in which Mr. Y is a member, whereas Mr.Y is willing to join the committee only if Mrs Z is included, how many such committee are possible?
Options- A. 91
- B. 104
- C. 109
- D. 98 Discuss
- 4. A team of 8 students goes on an excursion, in two cars, of which one can seat 5 and the other only 4. In how many ways can they travel?
Options- A. 126
- B. 120
- C. 146
- D. 156 Discuss
- 5. How many arrangements can be made out of the letters of the word DRAUGHT, the vowels never beings separated?
Options- A. 1440
- B. 720
- C. 360
- D. 640 Discuss
- 6. In a bag, there are 8 red, 7 blue and 6 green flowers. One of the flower is picked up randomly. What is the probability that it is neither red nor green ? A) 13 B)821 C)621 D)2021
Options- A. Option A
- B. Option B
- C. Option C
- D. Option D Discuss
- 7. In a group of 6 boys and 4 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there ?
Options- A. 205
- B. 194
- C. 209
- D. 159 Discuss
- 8. In how many different ways the letters of the word 'TRANSFORMER' can be arranged such that 'N' and 'S' always come together?
Options- A. 112420
- B. 85120
- C. 40320
- D. 1209600 Discuss
- 9. What is the value of 100P2 ?
Options- A. 10000
- B. 9900
- C. 8900
- D. 7900 Discuss
- 10. How many such pair of letters are there in the word ?TROUBLED? which have as many letters between them in the word as they have between them in the English alphabet?
Options- A. 2
- B. 3
- C. 4
- D. 5 Discuss
Permutation and Combination problems
Search Results
Correct Answer: 4320
Explanation:
Given Word is PROMISE.
Number of letters in the word PROMISE = 7
Number of ways 7 letters can be arranged = 7! ways
Number of Vowels in word PROMISE = 3 (O, I, E)
Number of ways the vowels can be arranged that 3 Vowels come together = 5! x 3! ways
Now, the number of ways of arrangements so that three vowels should not come together
= 7! - (5! x 3!) ways = 5040 - 720 = 4320.
Correct Answer: 90,720
Explanation:
The given word HAPPYHOLI has 9 letters
These 9 letters can e arranged in 9! ways.
But here in the given word letters H & P are repeated twice each
Therefore, Number of ways these 9 letters can be arranged is
Correct Answer: 91
Explanation:
We first count the number of committee in which
(i). Mr. Y is a member
(ii). the ones in which he is not
Case (i): As Mr. Y agrees to be in committee only where Mrs. Z is a member.
Now we are left with (6-1) men and (4-2) ladies (Mrs. X is not willing to join).
We can choose 1 more in5+
=7 ways.
Case (ii): If Mr. Y is not a member then we left with (6+4-1) people.
we can select 3 from 9 in
=84 ways.
Thus, total number of ways is 7+84= 91 ways.
Correct Answer: 126
Explanation:
There are 8 students and the maximum capacity of the cars together is 9.
We may divide the 8 students as follows
Case I: 5 students in the first car and 3 in the second
Case II: 4 students in the first car and 4 in the second
Hence, in Case I: 8 students are divided into groups of 5 and 3 in8C3 ways.
Similarly, in Case II: 8 students are divided into two groups of 4 and 4 in 8C4ways.
Therefore, the total number of ways in which 8 students can travel is:
=56 + 70= 126
Correct Answer: 1440
Explanation:
There are 7 letters in the word DRAUGHT, the two vowels are A and U. Since, the vowels are not to be separated, AU can be considered as one entity. Therefore, the number of letters will be 6 instead of 7. The permutations will be P(6,6) = 6! ways.
But the two vowels A and U can be arranged in two ways, i.e. AU and UA. The required number of arrangements = 2!.6! = 1440 ways.
Correct Answer: Option A
Explanation:
Total number of flowers = (8+7+6) = 21.
Let E = event that the flower drawn is neither red nor green.
= event taht the flower drawn is blue.
--> n(E)= 7
--> P(E)= =
Correct Answer: 209
Explanation:
We may have (1 boy and 3 girls)or(2boys and 2 girls)or(3 boys and 1 girl)or(4 boys).
Required number of ways = (
) +
+ (
) + (
)
= (24+90+80+15)
= 209.
Correct Answer: 1209600
Explanation:
Given word is TRANSFORMER.
Number of letters in the given word = 11 (3 R's)
Required, number of ways the letters of the word 'TRANSFORMER' can be arranged such that 'N' and 'S' always come together is
10! x 2!/3!
= 3628800 x 2/6
= 1209600
Correct Answer: 9900
Explanation:
Here in 100P2, P says that permutations and is defined as in how many ways 2 objects can be selected from 100 and can be arranged.
That can be done as,
= 100!/(100 - 2)!
= 100 x 99 x 98!/98!
= 100 x 99
= 9900.
Correct Answer: 2
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.