SAT Question of the Day May 25th 2013

In a community of 416 people, each person owns a dog or a cat or both. If there are 316 dog owners and 280 cat owners, how many of the dog owners own no cat?

 

A.     36

B.     100

C.     136

D.     180

E.     316

This is a “set theory” question – best solved by drawing a Venn diagram.

Write in the left circle dog owners.Write in the right circle cat owners.

In the middle circle are people who own both.

If there are 416 people all together and there are 316+280=596 pets – that means there are 180 who are double counted.

Out of the 316 dog owners 180 have a cat. That implies there are 136 that own only a dog.

45% out of 275,000 got it right.

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