Mean weight of 34 students of a school is 42, kg . If weight of teacher be included, mean rises by 4

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The mean weight of $34$ students of a school is $42\, kg$. If the weight of the teacher be included, the mean rises by $400\, g.$ Find the weight (in $kg$) of the teacher.

A

$66$

B

$56$

C

$55$

D

$57$

Solution

Let the weight of teacher $=x kg$ and average weight of students and teacher $=42+.40=42.40 kg$

$34 \times 42+x=35(42.4) \Rightarrow x=1484-1428=56 kg$

Hence weight of the teacher is $56 kg$.

Standard 13

Quantitative Aptitude

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