[問題]GWD 09-37

[Flory]

A club with a total membership of 30 has formed 3 committees,M, S, and R, which have 8, 12, and 5 members, respectively. If no member of committee M is on either of the other 2 committees, what is the greatest possible number of members in the club who are on non of the committees?

A. 5
B. 7
C. 8
D. 10
E. 12

Ans: D ...how?

Thank you all~~ ^^

[Kyo]

M的成員與S, R不重複，所以至少有8人是有committees
剩下的假設R的5人與S全部重複，所以有committees的成員就是8 + 12 = 20，因此，剩下的就是10囉~

[zazer.lin]

A club with a total membership of 30 has formed 3 committees,M, S, and R, which have 8, 12, and 5 members, respectively. If no member of committee M is on either of the other 2 committees, what is the greatest possible number of members in the club who are on non of the committees?

A. 5
B. 7
C. 8
D. 10
E. 12

Ans: D ...how?

Thank you all~~ ^^

要注意紅色的那句話喔! 題目只說 M 的成員不能兼任 committee S 和 committee R, 並沒有說 S 和 R 的成員不能互相兼任喔!
所以the greatest possible number of members in the club who are on non of the committees:
total members - M - S (取 S 是因為假設 R 的 member 均兼任 S)
= 30 - 8 - 12
= 10

[Flory]

Thank you Kyo & Zazer Lin for your help! ^^