Question 313382
300 people were polled to see if a dog or cat were their favorite pet.
 185 likes dogs 130 liked cats and 75 people liked both.
 how many people didn't like either pet?
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What must i find? Find out how many liked only dogs and how many liked only cats
185 - 75 = 110 liked dog only
130 - 75 = 55 liked cats only
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What do i know?
 Pet lovers consist of three groups, dogs only, cats only, & both 
the total: 110 + 55 + 75 = 240
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What strategy should i use? 
Subtract pet lovers from 300
300 - 240 = 60 don't like either pet