Assuming probability of having a boy is P(B) = 1/2, and of having a girl is P(G) = 1/2,
the probability of having 3 boys for 4 kids (with out regard to the girl to be the first,
second, third or fourth kid) is;
P(3B1G) = 4C3 [P(B)]4 = 4 (1/2)4 = 0.250 = 25%
The factor 4 comes because there are 4 possibilities for the order in which the girl can
come out.
3/8
1/32
If we consider there is a 50% chance for having a boy and 50% for having a girl*, there is : - 12,5% chance of having no boys; - 37,5% chance of having 1 boy; - 37,5% chance of having 2 boys; - 12,5% chance of having 3 boys. Therefore, there is 50% chance of having at least two boys. *The odds are more like 51% for having a boy and 49% for having a girl, but it doesn't really matters.
1/35
6 out of 9.
1/8
1/4
3/8
These events are independent; so the probability of a girl is 0.5.
1/32
50%
The probability of having a boy or a girl is always 50/50 each time, regardless of previous outcomes. So the theoretical probability of having a girl after having three boys in a row is still 50%.
(assuming that the probability of having a girl or a boy is 50/50) Looking from beforehand, the probability of having three boys then a girl is the probability of each of these events happening multiplied together. That is 50% x 50% x 50% x 50% or 0.54 This would mean that the chance of having a girl after three boys is 0.0625. If you've already had the three boys though, it is a different story. The point is that previous experiences do not affect future ones; probability has no memory. Thus the probability of having a girl next is 50%, regardless of if you've had boys or girls in the past. To think otherwise is known as the gambler's fallacy, where a gambler says "black has come up 4 times in a row, it must be red next" even though the chance of red is always 50%
If we consider there is a 50% chance for having a boy and 50% for having a girl*, there is : - 12,5% chance of having no boys; - 37,5% chance of having 1 boy; - 37,5% chance of having 2 boys; - 12,5% chance of having 3 boys. Therefore, there is 50% chance of having at least two boys. *The odds are more like 51% for having a boy and 49% for having a girl, but it doesn't really matters.
1/35
9 kids total. 3 boys3 out of 9 = 3/9 = 1/3
Assuming that the probability of having a baby girl is 1/2 and that of having a baby boy is 1/2, the probability of having 3 baby girls in a row is (1/2)(1/2)(1/2)=1/8.