Question

The average weight of $5$ children is increased by $2$ kg when one of them who weight $30$kg is replaced by another child.What is the weight of the new entrant

• A. $25$kg
• B. $30$kg
• C. $55$kg
• D. $40$kg

Answer 1

The correct option is D $40$kg

The average weight of $5$ children $=x$

Sum of children's weight $=5x$

Weight of the new children$=y$

then

$\frac{5x-30+y}{5}=x+2$

$\Rightarrow 5x-30+y=5x+10$

$\Rightarrow y=10+30$

$\therefore y=40kg$