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.
Shareef said:
10 years ago
Why 4 is taken?
Sanjana said:
10 years ago
Can the clear explanation of this problem can be given by someone? Since I dint get it.
Haribabu said:
1 decade ago
Why are you taking 10c4 so many ways like 10c2, 10c5?
If I take total 10 letters, so I calculate 10! = (10*9*8*7*6*5*4*3*2*1).
So please explain clearly.
If I take total 10 letters, so I calculate 10! = (10*9*8*7*6*5*4*3*2*1).
So please explain clearly.
Onkar said:
1 decade ago
We can't use permutation here because they have mentioned that no repetition is permissible and in 4 number word only possible solution is 210. 10C4 = 210.
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.
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.
Santhosh said:
1 decade ago
I have so much confusion at the answering problem,
"where we use the permutation formula and combination formula"?
Please anyone tell me.
"where we use the permutation formula and combination formula"?
Please anyone tell me.
Ashutosh Sharma said:
1 decade ago
Which formula is used to solve this problem?
Pradeep said:
1 decade ago
Its very easy, no need to get confused with permutation.
Divide the statement in two part.
From given 10 character, we have to choose 4 of them only.
So, 10C4 = 10*9*8*7/4! = 210.
Now we have to arrange there 4 character.
So, it would be simply 4! because there is no repetition of word.
Total - 210*24 = 5040.
Moral - choose 4 word out of 10 then arrange them by 4!.
Divide the statement in two part.
From given 10 character, we have to choose 4 of them only.
So, 10C4 = 10*9*8*7/4! = 210.
Now we have to arrange there 4 character.
So, it would be simply 4! because there is no repetition of word.
Total - 210*24 = 5040.
Moral - choose 4 word out of 10 then arrange them by 4!.
(1)
Motunrayo said:
1 decade ago
Please I want to know when to use combination and permutation.
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