Permutations.....

\hspace{-16}$(1)\;\; $\mathbf{4}\;$ married Couple are to be seated on a Round Table\\\\ The No. of ways in which husband and wife are Diagonally Opposite is\\\\\\ $(2)\;\; $The no. of No.,s greater then $\mathbf{50,000}$ that can be formed\\\\ by using the Digits $\mathbf{3,5,6,7,9}$ is

4 Answers

71
Vivek @ Born this Way ·

For first, Is it 6 ? (I'm not very sure though)

For second, all numbers who start without 3, are greater than 50,000. So, If repetition of digits is ignored, It should be 5!-4!.

If repetition is allowed, the should it be 55- 45 ?

262
Aditya Bhutra ·

1) i think it is 48

2) i think it means repetition is not allowed.
Greater = Total - Smaller = 5! - 4! (Same as Vivek)

1057
Ketan Chandak ·

i too agree wid aditya.....first seat a man and his wife diagonally...
the next man can seat in 6 ways and his wife in only 1 way...
similarly its 4 x 1 and 2 x 1 for the next and its following pair....

thus final answer turns out to be 6 x 4 x 2=48

71
Vivek @ Born this Way ·

Okay! Yes

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