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Need help with two Permutation & Combinatorics questions

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by earth@work » Thu Dec 11, 2008 6:16 pm
is the OA:
1)3*4! =72
let vowels I & A be together = 4P4*2=4! *2
total arrangements=5!
never together arrangements = 5!-2*4! =4!*3 = 72
2)6!*5!
Girls:6 boys:7; arrangements are:
G1B1G2B2G3B3G4B4G5B5G6 or G1G2B1G3B2G4B3G5B4G6B5 etc but the arrangement will be equal to 5!*6!
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