A teacher at a school wants to divide 15 children into two classes. The teacher

Question

A teacher at a school wants to divide 15 children into two classes. The teacher has two initial lists based on the previous year. List 1 contains the names of five girls and two boys, whereas list 2 contains the names of two girls and six boys. A name is randomly selected from list 1 and added to list 2. A name is then randomly selected from the augmented list 2. Given that the name selected from the augmented list 2 is a boy, what is the probability that a girls name was originally selected from list 1?

is this correct? and why?

Explanation / Answer

YES ITS CORRECT.

ITS BEEN ASKED PROBABILITY OF GIRL BEEN SELECTED FROM LIST 1

THEREFORE ITS PROBABILITY WILL BE 5/7.

ALSO ITS A CASE OF SELECTION THEREFORE SO THE PROBABILITY OF GIRL TO BE IN LIST TWO BECOMES 3/9.

COMBINING BOTH IT BECOMES 3/9*5/7

TOTAL NUMBER OF CASES WILL BE 3/9*5/7 + 7/9*2/7

HENCE THE ANSWER WILL BE 0.5173

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