Question

the average mask donated by 50 students is 30.when the class teacher donated mask then average increased by 1. how many donated by teacher​

Answer 1

$Given \: average \:mask \:donated\:by$

$50 \:students = 30$

$Sum \: of \:the \:mask = 30 \times 50$

$= 1500 \: --(1)$

$Let \: number \:of \:mask \: donated \:by \:a$

$class \:teacher = x$

$New \: average = 30 + 1 \:(given)$

$\implies \frac{Sum \:of \:the \:mask}{ total \:members } = 31$

$\implies \frac{1500+x}{51} = 31$

$\implies 1500+x = 31 \times 51$

$\implies x = 1581 - 1500$

$\implies x = 81$

Therefore.

$\red{ Number \:of \:mask \: donated \:by \:teacher }$

$\green { = 81 }$

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