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 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 one
A) 1/15 B) 1/5 C) 4/15 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(1/5(x/2))=1/10(x)---&gt;non major=x/2-1/10(x)=2/5(x)   hence 2/5   2/5
<result>E</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 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?