Mean marks of 10 boys in a class is 70 % , whereas mean marks of 15 girls is 60 % . mean marks of al

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The mean marks of $10$ boys in a class is $70 \%$, whereas the mean marks of $15$ girls is $60 \%$. The mean marks of all the $25$ students is

A

$64$

B

$60$

C

$55$

D

$52$

Solution

The mean marks of $10$ boys $=70 \%$

Total marks of $10$ boys $=70 \% \times 10=700 \%$

The mean marks of $15$ girls $=60 \%$

Total marks of $15$ girls $=60 \% \times 15=900 \%$

$\therefore$ Sum of the total marks of $25$ students

$=700+900=1600 \%$

$\therefore$ The mean marks of all the $25$ students

$=\frac{1600}{25}=64 \%$

Standard 13

Quantitative Aptitude

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