question_answer

The arithmetic mean of the scores of a group of students in a test was 52%. The brightest 20% of them secured a mean score of 80 and the dullest 25%, a mean score of 31 %. Which of the following is the mean score of the remaining 55%?

A) 45%                       

B)        50%

C) 51.4% (approx)

D)        54.6% (approx)