At the university entrance exam, a candidate is admitted according to whether he has passed or failed the test. Of the candidates who are really capable, 80 % pass the test and of the incapable, 30 % pass the test. Given that 40 % of the candidates are really capable, then the proportion of the really capable students who can pass the test to the total students who can pass is about ?

Correct Answer: 16\/25

If there are total 100 candidates, 40 candidates are really capable and 60 candidates are incapable.Of the candidates who are really capable = 80% 40*(80/100)=32 pass the test andof the incapable= 30%60*(30/100)=18 pass the test.Total candidates who passed the test = 32+18 = 50The proportion of the really capable students who can pass the test to the total students who can pass = 32/50 = 16/25.