How many members are in both Club X and Club Y?
(1) There were 15 members at the joint conference for members of Club X and Club Y, and no members were absent.
(2) Club X has 6 members and Club Y has 12 members.
OA: C
I don't understand why A) is incorrect answer. Question asks the total # of members in both clubs.
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Club X and Club Y
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shankar.ashwin
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From (1) you know, there are a total of 15 people, but we dont know how many were a part of both X and Y (intersection)
From (2) we know n(x)=6 and n(y)=12, but we still dont know how many were part of both.
Together we know, n(x U y) = n(x) + n(y) - N(XY)
We need to find n(XY) = n(x) + n(y) - n(x U Y) = 6+12-15 = 3
Hence c
From (2) we know n(x)=6 and n(y)=12, but we still dont know how many were part of both.
Together we know, n(x U y) = n(x) + n(y) - N(XY)
We need to find n(XY) = n(x) + n(y) - n(x U Y) = 6+12-15 = 3
Hence c
