A Gentleman has 6 spare rooms for guests. In how many ways can he accommodate 3 guests, each in a separate room?
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There are 6 rooms and only 3 have to be selected. The order of the room matters so we have to use permutation. 6P3=120
oopps it was a tricky one
There are 6 spare rooms. 3 rooms can be selected of the 6 by 6C3=20.
The 3 guests can be arranged in 3 rooms by 3! ways=6
Total number of ways= 20x6= 120.
By using permutation we can solve.. That means the guest can be arranged in 6p3 ways
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Yeah, you're right. 6C3x3! Is the same as 6P3
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For combinations you would have to divide 120 for 3!(3x2x1), right? So you can only solve this problem through permutation.
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@Pedro Serzedelo – 6C3 [ (6!)/(3!3!) ]refers to selection of 3 objects(here rooms) out of 6. And then we multiply 3! to assure all possible arrangements of these objects (people in the 3 rooms). So we get 6C3x3!.
Where as 6P3 [ 6!/3! ] takes care of both selection and arrangement. This is why they are the same.
Thanks for giving such nice solution
The first guest can be accommodated in any of the 6 different rooms. The second guest can be accommodated in any of the 5 remaining rooms. The third guest can be accommodated in any of the 4 remaining rooms. Therefore, total number of ways in which the guests can be accommodated= 6x5x4 = 120 :D :D
6!/3! . you get this how. there are 6 choice. so 6! but 3 geusts so6!/3!
6 options...3 choices => \frac { 6! }{ 3! }
3! x 6 C 3 or 6 P 3 = 6 X 5 X 4 = 120
First: 6 ways;
Second: 5 ways;
Third: 4 ways;
Consecutive events: AND multiplication.
Using permutation, 6P3 = 120.
it's like a simple problem: how many do you have to write a 3-number number from 6 numbers. and the answer will be: 6x5x4 = 120
is permutations of 6 over 3. 6 factorial over (6-3) factorial equals to120
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there are 3 guests ,, each guest should have a separate room .. for this first guest has 6 choices of selecting his room.. he selects one room for him then second guest has 5 choices and he selects one room .. third guest has 4 choices... therefore 6 * 5 * 4=120 hence solved.. 120 is the ans.. :)