400 students took a mock exam in Delhi, 60% of the boys and 80% of the girls cleared the cut off in the examination. If the total percentage of students qualifying is 65%, how many girls appeared in the examination?  Choose the correct option.
A) 50 B) 100 C) 120 D) 140 E) 180

Rationale: 60 % * x + 80 % * ( 400 - x ) = 65 % * 400 ans = 100 answer : b
Answer: B