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 3 of 7.
AISH said:
1 decade ago
If position of word matter (no repetition allowed) Then we have to use permutation.
And if no position matter we have to use combination.
And if no position matter we have to use combination.
Chandani said:
1 decade ago
When we form LOGA and AGOL it is permutation but in combination we don't write like r, s is similar to s, r -in combination, not in permutation. So in above question we are not allowed to double the letter but are allowed to use the same letter in different words. .
Vimal said:
1 decade ago
I am not clear with this. They gave a condition that repetition is not allowed. when we use 10p4, (i.e. is permutation) it satisfy the given condition?
Satish said:
1 decade ago
Please tell me that when we should use permutations and when we should combinations with an example?
Akash said:
1 decade ago
What does the exclamation mark imply? please can someone explain this question?
(1)
Yazhini said:
1 decade ago
! implies that it is a multiplication sign up to 1. It is neither a permutation nor a combination. For ex 4! implies that 4*3*2*1=24. is it clear guy?
Shashwat said:
1 decade ago
Why permutation is used explain?
Shivam said:
1 decade ago
I'm confused for in which question we do permutation and combination. I have used combination in this question but I was wrong. But some other questions which as same as this question solved by combination. Why did you use permutation on this?
Motunrayo said:
1 decade ago
Please I want to know when to use combination and permutation.
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)
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