【問題】GWD18-20

[little8]

Q20:
Last year in a group of 30 businesses, 21 reported a net profit and 15 had investments in foreign markets. How many of the businesses did not report a net profit nor invest in foreign markets last year?
(1) Last year 12 of the 30 businesses reported a net profit and had investments in foreign markets.
(2) Last year 24 of the 30 businesses reported a net profit or invested in foreign markets, or both.

這題很明顯單就(1)可算出答案,所以A沒問題..可是答案卻是D
請問(2)畫線的部分句意識什麼?我想我可能是因為沒有讀懂,所以無法算出答案..

感謝~

[kwtluck]

a net profit or invested in foreign markets,or both. =>"聯集"的意思, (A聯集B)=(A)+(B)-(A交集B)

[little8]

a net profit or invested in foreign markets,or both. =>"聯集"的意思, (A聯集B)=(A)+(B)-(A交集B)

喔..這樣我了解了,所以B就是 30-24=6就得到答案了

謝謝妳