BedokFunlandJC

[IQ Challenge]

 

Q1. If a couple has two children (born 1 year apart and have different names), given that at least one of them is a girl,

what is the probability that both children are girls?

 

Q2 If a couple has two children (born 1 year apart and have different names), given that at least one of them is a girl,

and that this girl is named Ah Lian, what is the probability that Ah Lian's sibling is also a girl?

 

Q3 Why are the correct answers to the Q1 & Q2 different?

Quote 0 0
BedokFunlandJC
Ans to Q1 is 33%

Ans to Q2 is 50%

For Ans to Q3, see https://en.wikipedia.org/wiki/Boy_or_Girl_paradox
Quote 0 0
BedokFunlandJC
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1.

Q1) ... ... the host, who knows what's behind all the doors, opens another door, say No. 3, to reveal a goat. The host then says to you, "Do you want to switch to the other closed door?". Is it to your advantage to switch your choice?

Q2) ... ... your friend in the audience, who doesn't know what's behind all the doors, runs onto the stage and opens another door, say No. 3, to reveal a goat. The host then says to you, "Do you want to switch to the other closed door?". Is it to your advantage to switch your choice?

Q3)  Why are the correct answers to Q1 & Q2 different?
Quote 0 0