Random Double Matrix Question #3

May 16, 2011: International Double Matrix month is half over.  Have you become an expert at solving Double Matrix questions yet?

What’s a Double Matrix question? 

For those who missed the first article in this series, a Double Matrix question (also known as an Overlapping Sets question) is one that involves a certain population where each member of that population has two characteristics associated with it.  Questions that fall into this category can often be solved using the Double Matrix Method.

For an introductory lesson on the Double Matrix Method, please watch the video at http://www.youtube.com/watch?v=OWD2t5jCCZQ

Afterwards, you can try solving this super difficult question:

In a group of 1000 people, each person is either left-handed or right-handed but not both.  80% of the females are left-handed, and 84% of the right-handed people are male.  How many people are right-handed?

1) There are 600 males in the group

2) There are 180 left-handed males in the group

Once you’ve attempted the question, you can watch the video solution below:

http://www.youtube.com/watch?v=dOZ9KM1m5Hs

Cheers,

Brent