SOLUTION: There are 4 boys and 3 girls. What is the probability the boys and girls sit alternately? Ans 1/35

Question 313342: There are 4 boys and 3 girls. What is the probability the boys and girls sit alternately?
Ans 1/35
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
you can have:

bgbgbgb

The probability that the first slot will be taken by a boy is 4/7
the probability that the second slot will be taken by a girl is 3/6
The probability that the third slot will be taken by a boy is 3/5
Then 2/4
Then 2/3
Then 1/2
Then 1/1

the probability that all of this will occur is 4/7 * 3/6 * 3/5 * 2/4 * 2/3 * 1/2 * 1/1 which comes out to be (4*3*3*2*2*1*1)/(7*6*5*4*3*2*1) which comes out to be 1/35.

Since this arrangement can only happen in one way, then that's your answer.

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