Asking The Right Question

Here’s a question for you:

John has two children. At least one of them is a boy.

What’s the probability that the other child is a girl?

…

Decide on an answer before moving on.

…

Ready?

…

Ok!

Intuitively, most people would guess that there’s a 50% chance that the other child is a girl.

If that’s your guess, keep reading, because that’s the wrong answer.

Here’s how it works.

With two existing children, there are four possible scenarios:

Now since we know that John has at least one boy, we can eliminate the second scenario and have 3 possible outcomes:

Among these 3 outcomes, 2 of them include a girl. So the answer is 2/3, or 66%.

This answer might seem weird because although the question is:

Given two children with at least one of them being a boy, what’s the probability that the other child is a girl?

… you might have been thinking of this question instead:

What’s the probability of a parent having a baby girl?

The answer to the first question is 66%, while the answer to the second question is 50%.

This small example highlights the importance of understanding the question before looking for the answer.

People are often busy trying to find answers, but few question whether they truly understand the question they are asking.

Why is this important?

Because unless you understand the question, you wouldn’t recognize the right answer even if it were right in front of you.

Worse, you may think you have the right answer, when it is actually the right answer to a different question.

12 Comments

Rob June 30, 2015 at 5:47 am - Reply

Not sure what your point is. Hence I am unable to determine whether it is helpful to forex trading. If you go any further with this, it would be helpful to define what is “right” in this context. Helpful in what sense? Factual? Moral? Financial (as in outcome)? Confidence? Process?
- Chris Lee June 30, 2015 at 6:20 am - Reply
  
  Hi Rob, the point is to understand what you’re trying to do by examining the question you’re trying to answer. This applies to everything we try to do.
Okeke June 30, 2015 at 8:22 am - Reply

Chris, sometimes examining the question only leads to more and more questions.
- Chris Lee June 30, 2015 at 9:47 am - Reply
  
  Yes, it sometimes does. But usually, if you ask the right question(s), no further questions are needed…
Berthram June 30, 2015 at 8:25 pm - Reply

Chris,
I put the same question to my two sons Fred & Divine. Their answer was 50% however i explained to them before they understood.
I totally agree with you that a lot of us do not understand the question before providing answers however its not possible that every one should understand or what do you think.
- Chris Lee