Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 1/2 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?	Choose the correct choice from the following choices.
A) 1/15 B) 1/5 C) 9/20 D) 1/3 E) 2/5
tot students=x   1st year student=x/2----&gt; non majaor=4/5(x/2)-----&gt; maj=1/5(x/2)   2nd year student=x/2----&gt;maj=1/2(1/5(x/2))=1/20(x)---&gt;non major=x/2-1/20(x)=9/20(x)   hence 9/20   9/20
<result>C</result>
Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 1/2 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?