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Please help i need this done in 5 mins

Please help i need this done in 5 mins-example-1
User XDrago
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1 Answer

4 votes

Answer:

0.233 or
(7)/(30)

Explanation:

Pre-Solving

We are given that 12 people have a brother and a sister, 7 people have a sister but don't have a brother, 3 have a brother but don't have a sister, and 8 don't have either.

We want to find the probability that a random student has a sister but doesn't have a brother.

Recall that probability is
( favorable outcomes)/(total outcomes)

So, we have 7 favorable outcomes (7 people that have a sister but don't have a brother), and when we add the total number of people together, we get 30 (the total number of people surveyed, aka our total outcomes).

Solving

Divide 7 by 30.


(7)/(30)

We can simplify this:

0.233

User DaveU
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