作者yangboxx (鸟)
看板TransBioChem
标题[生物] 想请问一题普生
时间Fri Jul 31 13:38:36 2015
14. John and Mary are planning to start a family. John was married once
before, and he and his first wife had a child with cystic
fibrosis. The brother of his current wife, Mary, died of cystic fibrosis.
What is the probability that John and Mary will have a
baby with cystic fibrosis? (Neither John, Mary, nor their parents have cystic
fibrosis.)
A) 1/4 B) 1/6 C) 1/8 D) 1/12 E) 1/16
答案是B
我的想法是
John是Tt，Mary是TT或Tt，所以不是1/2×1/4=1/8吗!?
先谢谢各位大大~~
--
※ 发信站: 批踢踢实业坊(ptt.cc), 来自: 114.40.160.48
※ 文章网址: https://webptt.com/cn.aspx?n=bbs/TransBioChem/M.1438321118.A.A56.html
1F：推 BiGiLa: Mary TT/Tt机率并不是一半一半喔 TT1/3 Tt2/3 07/31 14:17
2F：→ BiGiLa: 1/2 X( 2/3 X 1/2 ) = 1/6 07/31 14:18
3F：→ yangboxx: 对喔!!谢谢大大~~ 07/31 14:26