5. If the efficacy of a vaccine is 50% and coverage is 80%, what is effective vaccine coverage?
A. 30%
B. 40%
C. 50%
D. 80%
收錄日期: 2021-04-24 08:29:55
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https://hk.answers.yahoo.com/question/index?qid=20210203113301AAzqxR1