A group of students of arithmetic mean of the marks in a test was 63. The brightest 30% of them secured a mean score of 70 and the dullest 15% a mean score of 41. The mean score of remaining 55 % is A) 63.675 B) 61.785 C) 65.181 D) 66.67

1 Answer

Answer :

C)

Let the requird mean score be ‘x’

Then (30*70)+(15*41)+55x = 63*100

2100+615+55x=6300

2715+55x=6300

55x=3585

X=65.181


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