If average marks of three batches of 55,60 and 45 students respectively is 50,55 and 60 , then avera

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If the average marks of three batches of $55,60$ and $45$ students respectively is $50,55$ and $60 ,$ then the average marks of all the students is

A

$53.33$

B

$54.68$

C

$55$

D

$39.68$

Solution

Average marks of all students $=\frac{55 \times 50+60 \times 15+45 \times 60}{160}$

$=\frac{55 \times 5+6 \times 15+45 \times 6}{16}=\frac{275+90+270}{16}=\frac{635}{16}=39.68$

Standard 13

Quantitative Aptitude

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