SOLUTION: the mean marks in statistics of 100 students of a class was 72 the mean of marks of boys was 75 while there number was 70 find out the mean marks of girls in class.
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Question 435700: the mean marks in statistics of 100 students of a class was 72 the mean of marks of boys was 75 while there number was 70 find out the mean marks of girls in class. Answer by ewatrrr(24785) (Show Source):
Hi
If I am understanding Your question properly:
100*72 = 7200 Total scores for the class
total scores for the boys = 70*75 = 5250
7200-5250 = 1950 scores remaining for the 30 girls
1950/30 = 65 mean mark for the girls.
CHECKING our Answer***
.7*75 + .3*65 = 72