Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Probability (for me, this question is tough)

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OP

I already knew how to do it. But can u tell me your method?

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Original post by Elyn

I already knew how to do it.

Then what was the point of this thread

But can u tell me your method?

There is only one method

OP

Okay. Thank you

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Which method is used to answer this question ?

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Original post by zed963

Which method is used to answer this question ?

Can you do part (a)?

Original post by TenOfThem

Can you do part (a)?

Yes

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Original post by zed963

Yes

What did you get?

Original post by TenOfThem

What did you get?

5/22

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I Just tried solving this and got 25/99 which is well, near to 1/4 but not exact. This is what I did.

First I made a tree diagram for each family. For question a) I just did 1/3 * number of girls in family/total number of people in family for each of the 3 families and then added the 3 results up to get: 5/9

For question b) I just did 5/9 * 5/11 = 25/99

Anyone can tell me where I went wrong? Thanks

OP

For part (b), that is probability of condition events, P(C/G).

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Original post by zed963

5/22

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How did you get that

The chance of a girl from family A is

\frac{1}{3}\times\frac{3}{4} = \frac{1}{4}

that is already greater than

\frac{5}{22}

Original post by TenOfThem

How did you get that

The chance of a girl from family A is

\frac{1}{3}\times\frac{3}{4} = \frac{1}{4}

that is already greater than

\frac{5}{22}

lol I don't know maybe in a year i'll tell you.

Original post by zed963

lol I don't know maybe in a year i'll tell you.

ok

:smile:

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