probability

Totally there are 11! possible permutations (11 flowers)

Now, for the same type of flowers not together, the only possible pattern is RCRCRCRCRCRCR where R and C represent rose and chrys resp.

For the roses there are 6! possible permutations

For the chrys there are 5! possible permutations.

So the no. of possible permutations of this patter is 6! x 5!


Finally prob. required = (6! x 5!)/11! = 1/462

R = rose C= chrysanthemums

P(flowers of the same type are not placed next to each other)
=P(RCRCRCRCRCR)
=(6/11)(5/10)(5/9)(4/8)(4/7)(3/6)(3/5)(2/4)(2/3)(1/2)(1)
=1/462


希望幫到你!