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.
Ankur said:
1 decade ago
It should be done in simple way i.e. 10 c4 = 210 ways then 4 letters can be written in 4! i.e 24 therefore 210*24 = 5040.
Shree Hemalatha said:
1 decade 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 ?
Preethi said:
1 decade ago
Why we used permutations here and why not combinations.
Please explain clearly when we use npr and when we use ncr.
Please explain clearly when we use npr and when we use ncr.
VAIBHAV said:
6 years ago
10C4 *4!
10C4 = (10*9*8*7) / (4*3*2*1) =(10*3*7) = 210,
4! = 4 * 3 * 2 * 1 = 24.
So Obviously, 10C4 * 4! = 5040.
10C4 = (10*9*8*7) / (4*3*2*1) =(10*3*7) = 210,
4! = 4 * 3 * 2 * 1 = 24.
So Obviously, 10C4 * 4! = 5040.
(5)
Nithesh said:
8 years ago
There is not repetition getting, Logarithm all the words are different.
So permutations are taken.
Am I right?
So permutations are taken.
Am I right?
Timothy Githinji said:
1 decade ago
I'm also wondering why we are using permutations here. According to the question no order is required.
Jagadeesh said:
1 decade ago
How here permutation is used when there is condition letters should not be repeated?
Please explain.
Please explain.
Satish said:
1 decade ago
Please tell me that when we should use permutations and when we should combinations with an example?
Nandu said:
1 decade ago
@Santosh.
If you see "SELECT" then use "ncr" and if you see "ARRANGE" use npr.
No confusion.
If you see "SELECT" then use "ncr" and if you see "ARRANGE" use npr.
No confusion.
CLIFORD said:
3 years ago
We select 4 letters from LOGARITHMS in 10C2 then we arrange the 4 letters in four factorials.
(2)
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