General Questions
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The word ‘DELHI’ contains 5 letters
Therefore, required number of words = 5P5 = 5! = (5 × 4 × 3 × 2 × 1) = 120
120 words can be formed by using letters of the word ‘DELHI’
The word 'LEADER' contains 6 letters, namely 1L, 2E, 1A, 1D and 1R.
Required number of ways = |
6! |
| (1!)(2!)(1!)(1!)(1!) | |
| = 360. |
The word 'LEADING' has 7 different letters.
When the vowels EAI are always together, they can be supposed to form one letter.
Then, we have to arrange the letters LNDG (EAI).
Now, 5 (4 + 1 = 5) letters can be arranged in 5! = 120 ways.
The vowels (EAI) can be arranged among themselves in 3! = 6 ways.
Required number of ways = (120 x 6) = 720.
We may have (3 men and 2 women) or (4 men and 1 woman) or (5 men only).
Required number of ways
| = (7C3 x 6C2) + (7C4 x 6C1) + (7C5) | ||||||||||||
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| = (525 + 210 + 21) | ||||||||||||
| = 756. |
We may have (1 boy and 3 girls) or (2 boys and 2 girls) or (3 boys and 1 girl) or (4 boys).
Required number of ways
| = (6C1 x 4C3) + (6C2 x 4C2) + (6C3 x 4C1) + (6C4) | ||||||||||||||||||||
| = (6C1 x 4C1) + (6C2 x 4C2) + (6C3 x 4C1) + (6C2) | ||||||||||||||||||||
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| = (24 + 90 + 80 + 15) | ||||||||||||||||||||
| = 209. |
Required number of ways
| = (8C5 x 10C6) | ||||||||
| = (8C3 x 10C4) | ||||||||
|
||||||||
| = 11760. |
There are 6 letters in the given word, out of which there are 3 vowels and 3 consonants.
Let us mark these positions as under:
(1) (2) (3) (4) (5) (6)
Now, 3 vowels can be placed at any of the three places out 4, marked 1, 3, 5.
Number of ways of arranging the vowels = 3P3 = 3! = 6.
Also, the 3 consonants can be arranged at the remaining 3 positions.
Number of ways of these arrangements = 3P3 = 3! = 6.
Total number of ways = (6 x 6) = 36.
Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4)
| = (7C3 x 4C2) | |||||||||
|
|||||||||
| = 210. |
Number of groups, each having 3 consonants and 2 vowels = 210.
Each group contains 5 letters.
| Number of ways of arranging 5 letters among themselves |
= 5! |
| = 5 x 4 x 3 x 2 x 1 | |
| = 120. |
Required number of ways = (210 x 120) = 25200.
In the word 'CORPORATION', we treat the vowels OOAIO as one letter.
Thus, we have CRPRTN (OOAIO).
This has 7 (6 + 1) letters of which R occurs 2 times and the rest are different.
| Number of ways arranging these letters = | 7! | |
| 2! |
Now, 5 vowels in which O occurs 3 times and the rest are different, can be arranged
| in | 5! | = 20 ways. |
| 3! |
Required number of ways = (2520 x 20) = 50400.
Required number of ways
= (7C5 x 3C2) = (7C2 x 3C1)
| = | ![]() |
7 x 6 | x 3 | ![]() |
| 2 x 1 |
= 63.

