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Bunuel
In how many ways can 5 boys and 4 girls be arranged in a line so that there will be a boy at the beginning and at the end?


(A) 3!/5! * 7!

(B) 5!/6! * 7!

(C) 5!/3! * 7!

(D) 3!/5! * 7!

(E) 5!/7! * 7!

The way the answers are given , thought that 7! is in the denominator.

B-------B
5*7*6*5*4*3*2*1*4
That's option C
\(\frac{5!}{3!}*7!\)
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Slight confusion.

When we say 7!, aren't we considering all 7 elements to be distinct ? Where as there are 3 Boys and 4 Girls. Why are we considering each boy to be different and each girl to be different ?

Will appreciate a response.
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altairahmad
Slight confusion.

When we say 7!, aren't we considering all 7 elements to be distinct ? Where as there are 3 Boys and 4 Girls. Why are we considering each boy to be different and each girl to be different ?

Will appreciate a response.
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Bunuel
altairahmad
Slight confusion.

When we say 7!, aren't we considering all 7 elements to be distinct ? Where as there are 3 Boys and 4 Girls. Why are we considering each boy to be different and each girl to be different ?

Will appreciate a response.
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Aren't all people different?

How can I determine if B1B2b3B4 are to be taken as 4 distinct objects or same ? I am comparing this scenario to ABCCADA. The letters are repeating, much like the boys and girls in this question. Why didn't we divide the Boys and Girls 7! by 4! X 3!.

Thanks againm

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Bunuel
In how many ways can 5 boys and 4 girls be arranged in a line so that there will be a boy at the beginning and at the end?


(A) 3!/5! * 7!

(B) 5!/6! * 7!

(C) 5!/3! * 7!

(D) 3!/5! * 7!

(E) 5!/7! * 7!

Number of ways of arranging 2 boys at the ends = 5p2 = 5!/3!

The remaining 7 people can be arranged in 7! Ways

So, total = 5!/3!*7!

Option C

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