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Rohan and Ekta go out to dinner. They invite 3 other couples. When everyone arrives they greet each other and some even shake hands with one another. However, no one shook hands with his or her own spouse.

At the end of the dinner, Rohan asks all the attendees "How many people did you shake hands with?"

They all reply with a number. The numbers are: 0, 1, 2, 3, 4, 5, 6.

How many people did Ekta shake hands with?

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marked as duplicate by Rand al'Thor, boboquack, Wen1now, Mithrandir, Sid Oct 4 '17 at 9:32

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Ekta shook hands with

3 people.

If someone shook hands with 6, his or her spouse shook hands with 0, then someone shook hands with only one person, and we know it is with the "6" one, so only his/her spouse can have shaken with 5 people in total (because 5 means "everyone else except yourself, your spouse and the "0" one)

With this logic, you can see that every couple sums to 6 hands shaken in order to fullfil the numbers: 0 and 6, 1 and 5, 2 and 4, 3 and ... 3.

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