It’s 120 minutes because it would be two hours but there not putting it into hours there putting it into minutes and 1 hour is 60 minutes so two hours is 120 minutes
It is given that boys and girls are equally likely so the probability of getting boy or girl on any birth is 1/2= 0.5
Now we know that getting boy or girl is independent of each other.
So getting boy or girl on previous birth does not affect the probability of getting boy or girl on next birth. So probability of getting boy or girl on each birth is same 0.5
The probability of getting baby boy on sixth birth given first five are girl is same as getting baby on sixth birth.
P(Getting boy on sixth birth ) = 1/2 = 0.5
So the probability of getting baby boy on sixth birth given first five are girl is 0.5