20% of the students in a class failed in an examination. Out of the students who failed, 75% were males. Male students who failed constitute 90% of the economically poor students in the class. What is the ratio of the number of economically poor students to the number of students in the class?
Answers.
A) 1:4  B) 1:5  C) 5:6  D) 1:6  E) None of these
Explanation :   Let, the total number of students in the class be 't' and the total number of students in the class who are economically poor be 'p'.   So,Total number of students who failed = t/5.   Total number of male students who failed are:-   =&gt;(3/4)×(t/5)=9p/10.   =&gt;p/t=1/6.   Hence,Number of economically poor students/Number of Students=1/6=1:6.   Answer : 1:6
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20% of the students in a class failed in an examination. Out of the students who failed, 75% were males. Male students who failed constitute 90% of the economically poor students in the class. What is the ratio of the number of economically poor students to the number of students in the class?