<p>the percent probablity that expectant parents who already have two daughters will have another daughter ?</p>
<p>such questions repeat a lot but i dont know how to solvethem :s</p>
<p>50%</p>
<p>The fact that they had 2 daughters has no bearing on the third being a daughter. So, it is a 50% chance of being either a boy or girl.
If it would have asked something like “What is the probability of parents having three daughters” then the answer would be 1/8, which is 12.5%. But the question you gave is saying that the first two daughters are already alive, thus having no bearing whatsoever on the third child.</p>
<p>sorry 
i didnt get it !! can u please try to explain in other way</p>
<p>50%, assuming that the fact that the first two children were girls has no effect on the third child. These are independent events. You also have to assume your expectant parents only have one more child.</p>
<p>Here is a much trickier question (likely won’t appear on an SAT). I have two children, and one of them is a girl. What is the probability that both are girls.</p>
<p>so i can say that XX x XY prodece XX XX XY XY so 50 percent ?
is that true ?</p>
<p>Pretty much.</p>
<p>:) thnq u…</p>