In a country (like ours), everybody wants a boy and not a girl child. So, a family would keep on having girl children until a boy is born, and they would stop reproducing after the desired boy is born (they don't abort girl children like we do). The probability of having boys and girls are equal for each pregnant woman. Then, at any given moment what would be ratio of boys and girls in that country ?In a country (like ours), everybody wants a boy and not a girl child. So, a family would keep on having girl children until a boy is born, and they would stop reproducing after the desired boy is born (they don't abort girl children like we do). The probability of having boys and girls are equal for each pregnant woman. Then, at any given moment what would be ratio of boys and girls in that country ?
10-Ans- Suppose, initially there are N couples and they have N babies.
Obviously, N/2 of the babies are boys and N/2 are girls.
Those N/2 couples (having girl child), reproduce again and get N/4 boys and N/4 girls.
Those N/4 couples (having girl child), reproduce again and get N/8 boys and N/8 girls.
Those N/8 couples (having girl child), reproduce again and get N/16 boys and N/16 girls.
.......
...This iterative process goes on for infinity.
So, at any given moment, let us say after any Kth iteration, the total number of boys will be:
(N/2) + (N/22) + (N/23) + (N/24) + ..... + (N/2K-1) + (N/2K)
The total number of girls will be:
(N/2) + (N/22) + (N/23) + (N/24) + ..... + (N/2K-1) + (N/2K)
So, at any given moment the ratio of boys and girls is = 1:1