In an acoustics class, 120 students are male and 100 students are female. 25% of the male students and 20% of the female students are engineering students. 20% of the male engineering students and 25% of the female engineering students passed the final exam. What percentage of engineering students passed the exam? Options.
A) 5 % B) 10 % C) 16 % D) 22 % E) none of these

Rationale: explanation : the number of female engineering students in the class is ( 20 / 100 ) × 100 = 20 . now , 25 % of the female engineering students passed the final exam : 25 . hence , the number of female engineering students who passed is 5 . there are 120 male students in the class . and 25 % of them are engineering students . hence , the number of male engineering students is ( 1 / 4 ) × 120 = 30 . now , 20 % of the male engineering students passed the final exam : - 20 . hence , the number of male engineering students who passed is 6 . hence , the total number of engineering students who passed is : ( female engineering students who passed ) + ( male engineering students who passed ) = > 5 + 6 = 11 . the total number of engineering students in the class is : ( number of female engineering students ) + ( number of male engineering students ) = = > 30 + 20 = 50 hence , the percentage of engineering students who passed is : - = > ( total number of engineering students passed / total number of engineering students ) × 100 . = > ( 11 / 50 ) × 100 . = > 22 % . answer : d
Answer: D