Question

A pupils marks were wrongly entered as $83$ instead of $63$. Due to that the average marks for the class got increased by half the number of pupils in the class. The number of pupils in the class is____

• A. $10$
• B. $20$
• C. $40$
• D. $73$

Answer 1

The correct option is C $40$

Lets take total number of pupils $=x$
So, As per question, Total increase in marks$=x\times \frac{1}{2}=\frac{x}{2}$
So , $\frac{x}{2}=83-63=20$
$x=40$