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 5 of 7.
PRABHA said:
2 decades ago
I HAVEA DOUDT : 1O C P MEANS 10X9X8X7/(1X2X3X4)
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?
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.
Vaishali.n said:
1 decade ago
How to know whether to use permutation or combination?
Sathya said:
1 decade ago
Permutation = when ordering is considered.
(means here to form a word ordering is important).
Whereas in
Combination - ordering is not considered.
(means here to form a word ordering is important).
Whereas in
Combination - ordering is not considered.
Timothy Githinji said:
1 decade ago
I'm also wondering why we are using permutations here. According to the question no order is required.
Kuldeep vijay said:
1 decade ago
Yes, when repetitions not allowed it is an ordering condition.
Hansh said:
1 decade ago
Why you have used permutation here? please tell me the repetions of 4 letters concept?
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. .
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