求教,数学.passion 题目

因为是作的莫考,所以没有题号,斑竹间量

does the decimal equivalent of P/Q ,where P and Qare positive integers ,contain only  finite number有限小数的问题 of nonzero digits?

1>>Q

2>Q=8

题就每看明白~~~~~

For what percent of those tested for a certain infection was the test accurate ,that is positive for those had the infection and negative for those who did not have the infection ?

1>Of those who tested positive for the infection ,1/8 did not have the infection

2>Of those tested for the infection 90% tested negative

ANS:E

我是这样想的,因为2>,所以10% positive,

又因为1>的条件7/8的positive have the infection

怎么能说是E呢?