[求助]NN帮忙解释下这个题的意思，没有看明白

Q35:

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

(1)     Of those who tested positive for the infection, 1/8did not have the infection.

(2)     Of those tested for the infection, 90 percent tested negative.