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 6 of 7.
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?
Lydia said:
1 decade ago
It can also be done in another way.
Number of ways of selecting 4 letters from 10 letters=10C4
=(10*9*8*7)/4!
Number of ways of arranging these 4 letters =4P4=4!
So, total number of words formed= [(10*9*8*7)/4!]*4! = 10*9*8*7 = 5040
Am I correct?
Number of ways of selecting 4 letters from 10 letters=10C4
=(10*9*8*7)/4!
Number of ways of arranging these 4 letters =4P4=4!
So, total number of words formed= [(10*9*8*7)/4!]*4! = 10*9*8*7 = 5040
Am I correct?
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?
Timothy Githinji said:
1 decade ago
I'm also wondering why we are using permutations here. According to the question no order is required.
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.
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
Ashutosh Sharma said:
1 decade ago
Which formula is used to solve this problem?
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.
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