Question

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. The mean score of the remaining 55% is

Answer 1

Answer:

51.4

Step-by-step explanation:

Let the total no. of students = 100

As the question says= 20×80+25×31+55×x=52×100

1600 + 775 + 55x = 5200

55x = 5200 - 1600 - 775

55x = 2825

x = 51.4