Question

if mean of marks of 215 boys of class is 42% and the sum of mean of marks of 15 girls of same class is 54% then find the mean of whole class

Answer 1

let the total marks be ' 100 marks '

mean of the marks of boys = 42 %

42 % of 100 = 42 marks

total number of boys = 215
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total marks of boys = 215 × 42 = 9030

mean of the marks of girls = 54 %

= 54 % of 100 = 54 marks

number of girls = 15
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total marks of girls = 15 × 54 = 810

total marks of boys and girls

= 9030 + 810 = 9840 marks

total number of boys and girls

= 215 + 15 = 230

Find the mean of whole class:
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= 9840 / 230 = 42.7 %

therefore,mean of the marks of whole class= 42.7%

Answer : mean = 42.7 %
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