Aptitude - Permutation and Combination - Discussion
Discussion Forum : Permutation and Combination - General Questions (Q.No. 12)
12.
How many 4-letter words with or without meaning, can be formed out of the letters of the word, 'LOGARITHMS', if repetition of letters is not allowed?
Answer: Option
Explanation:
'LOGARITHMS' contains 10 different letters.
| Required number of words | = Number of arrangements of 10 letters, taking 4 at a time. |
| = 10P4 | |
| = (10 x 9 x 8 x 7) | |
| = 5040. |
Discussion:
68 comments Page 4 of 7.
Chandu said:
1 decade ago
What is the answer if repetition is allowed?
Shree said:
8 years ago
Thanks for explaining the solution.
Prawin said:
1 decade ago
It is a four letter word ---- out of 10 repeatition is not allowed so first 10 we have 1 then out of nine wehave 1then out of 8 we have 1 then out of 7 we have 1 so 10*9*8*7=ans
Krishna Kumar said:
8 years ago
Formula for Permutation nPr= n!/(n-r!)
For 10P4= 10!/(10-4!).
=> 10!/6!.
=>10x9x8x7x6x5x4x3x2x1
--------------------------------------
6x5x4x3x2x1
=>6x5x4x3x2x1 in both numerator and denominator will get cancelled.
Hence 10x9x8x7=5040.
For 10P4= 10!/(10-4!).
=> 10!/6!.
=>10x9x8x7x6x5x4x3x2x1
--------------------------------------
6x5x4x3x2x1
=>6x5x4x3x2x1 in both numerator and denominator will get cancelled.
Hence 10x9x8x7=5040.
Swati said:
7 years ago
@Krishna Kumar.
Formula for Permutation nPr= n!/ (n-r!) *r!
Formula for Permutation nPr= n!/ (n-r!) *r!
Abdulrehman said:
7 years ago
Thanks to all for explaining.
Pritesh said:
1 decade ago
After Selecting the letters in(10 * 9 * 8 * 7) ways those letters can be re-arrange in 4! ways.....
So, according to me answer should be 5040 * 4!
So, according to me answer should be 5040 * 4!
Jagadeesh said:
2 decades ago
How here permutation is used when there is condition letters should not be repeated?
Please explain.
Please explain.
Shree Hemalatha said:
2 decades ago
Here why we are using permutation concept and also how we are saying 4 letters s not repeating?
Could me explain me ?
Could me explain me ?
Toni said:
5 years ago
What if we had a repetition of letters? Explain.
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