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Home » A couple has 2 children. What is the probability that both are boys. If it is known that one of them is a boy?A. B. C. D.
A couple has 2 children. What is the probability that both are boys. If it is known that one of them is a boy?
A. \frac{1}{3}
B. \frac{2}{3}
C. \frac{3}{4}
D. \frac{1}{4}
Binomial Distribution | CBSE | Class 12 | Exercise 32A | Maths | RS Aggarwal
A couple has 2 children. What is the probability that both are boys. If it is known that one of them is a boy?
A. \frac{1}{3}
B. \frac{2}{3}
C. \frac{3}{4}
D. \frac{1}{4}

The couple has two children and one is known to be boy,
The probability that the other is boy will be =
\frac{Favourable-outcome}{Total-outcome}
Total outcomes are 3 ,
The first child is a boy, the second girl
The first child is a girl, the second boy
The first child is a boy, second boy
The favourable outcome is one,
Thus, the probability that the other is boy will be
\Rightarrow 1 / 3
Hence, the correct option is a.

i

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