32,756 views
18 votes
18 votes
Guys pls help solve 8i. I have a huge test tomorrow
Also pls show full working out bc yeah

Guys pls help solve 8i. I have a huge test tomorrow Also pls show full working out-example-1
User Roger Layton
by
3.3k points

1 Answer

28 votes
28 votes

Answer:

7/8

Explanation:

This is a counting exercise. Think of the 200 persons that you have to separate into two groups:

1) A group that satisfies the condition of the question

2) A group that does not satisfy the condition

Then, count how many persons are in group 1, and divide that by the total (200). That is your probability.

For (i), you will find 175 persons in group 1. Even though there are many persons with not blue AND not fair hair, they are only in the group once, so don't count them double.

Then 175/200 = 7/8

In fact, you could reverse the question by counting how many people do not satisfy the condition. That group are the persons that have both blue eyes and fair hair. That is the only way to not satisfy the condition. That amount is 25, you can read it from the table.

The chance of being in that group is 25/200 = 1/8.

P(group 1) + P(group 2) = 1

So you now have two ways of getting your answer.

P(group 1) = 1 - 1/8 = 7/8.

User Kinbiko
by
3.7k points
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