SOLUTION: I've tried for the last hour to solve this problem but I can't figure this out. here's the problem: A company conducted a marketing survey for families with young children and

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Question 1071040: I've tried for the last hour to solve this problem but I can't figure this out.
here's the problem:
A company conducted a marketing survey for families with young children and found that 124 families own a Nintendo DS and 186 families own a Nintendo Wii. If 20 own a Wii and a DS, how many own either a Wii or DS, but not both?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
out of the families that have DS, 20 have both, so subtract them from the total to get 124 - 20 = 104.

out of the families that have WII, 20 have both, so subtract them from the total to get 186 - 20 = 166.

you now have 3 categories that are pure.

104 own DS only.
266 own WII only.
20 own both.

the total that own either a DS or a WII but not both are equal to 104 + 266 = 370.

you have to subtract 20 from each category because it is included in both.
it is included in DS and it is included in WII.