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Consider all the possible arrangements of the letters in the term "ALLSTARS." How many do not have two same letters next to each other?

 Apr 23, 2023
 #1
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The total arrangements is 8!, but the total arrangements where there are 2 same letters next to one another is 7! * 3, since it is 7! for each letter, A, L, and S. Then, there are 6! * 3 scenarios where two of the same letters are next to one another, either A and L, A and S, or L and S. Then, there are 5! arrangements where all letters are next to the other same letter. We then subtract everything, giving us 8! - (7!*3) - (6!*3) - 5!, or 22920.

 Apr 23, 2023
 #2
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Unfortunately, that's wrong, but nice try!

 Apr 23, 2023
 #3
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There are in total

8!2!2! total arrangements of letters

 

considering arrangements of letter where the two 'L's are right next to each other, we have

7!2! total arrangements

 

and we have the same amounts of arrangements for the two 'S's being rigth next to each other

 

So therefore, we have

8!2!2!27!2!+6! because we overcount a bit

 

so the answer is 4760

 Apr 23, 2023
 #5
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wrong, but thanks for trying

Guest Apr 23, 2023
 #4
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cycle:c=if((a[i]!=a[j] and a[j]!=a[k] and a[k]!=a[l] and a[l]!=a[m] and a[m]!=a[n] and a[n]!=a[r] and a[r]!=a[s]), goto end, goto next);end:print(a[i],a[j],a[k],a[l],a[m],a[n],a[r],a[s]),", ",;p=p+1;next:i=i+8;j=i+1;k=j+1;l=k+1;m=l+1;n=m+1;r=n+1;s=r+1;if(s< count a, goto cycle, 0);
;print">Total =", p

 

 

This computer code gives a total of: 2,220 permutations, where no 2 of the same letters are next to each other.

By the way, there are: 8! / 2!2!2! =5,040 permutations in total.

 Apr 23, 2023
 #6
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Edit: Guest who posted

cycle:c=if((a[i]!=a[j] and a[j]!=a[k] and a[k]!=a[l] and a[l]!=a[m] and a[m]!=a[n] and a[n]!=a[r] and a[r]!=a[s]), goto end, goto next);end:print(a[i],a[j],a[k],a[l],a[m],a[n],a[r],a[s]),", ",;p=p+1;next:i=i+8;j=i+1;k=j+1;l=k+1;m=l+1;n=m+1;r=n+1;s=r+1;if(s< count a, goto cycle, 0);
;print">Total =", p

was correct!

 Apr 23, 2023
edited by totalkoolnezz  Apr 23, 2023
 #7
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TYSM!!

 Apr 23, 2023

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