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cant a and b be swithed as 48

 Apr 22, 2020
edited by Guest  Apr 22, 2020
edited by Guest  Apr 22, 2020
 #1
avatar+252 
+1

number of permutations of whole;120

number of permutations with a and b together:24

number f permutations with c and d together: 24

number of where tey are both together(ab and cd): 12

24+24-12=36

120-36=84

 Apr 22, 2020
 #2
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+1

isn't a and b together 48 because you can switch them.

 Apr 22, 2020
 #3
avatar+252 
+1

oops forgot about that

48+48=96-12=84

 

36 permutation

 Apr 22, 2020

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