The arithmetic mean of the scores of a group of students in a test was 80. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is?
Options: A) A)101.4. B) B)111.7 C) C)102.27 D) D)115.1 E) E)121.2
Let the required means score be x. Then,   20 * 80 + 25 * 31 + 55 * x = 80 * 100   = 1600 + 775 + 55x = 8000   = 55x = 5625   = x = 102.27   Answer:102.27
<result>C</result>
The arithmetic mean of the scores of a group of students in a test was 80. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is?