Direction of each questions consist of a question followed by two statements numbered $\mathrm{I}$and $\mathrm{II}$:

What is the average height of the class?

$\left(\mathrm{I}\right)$ Average height of the class decreases by $1 \mathrm{cm}$ if we exclude the tallest person of the class whose height is $56 \mathrm{cm}$.

$\left(\mathrm{II}\right)$ Average height of the class increases by $1 \mathrm{cm}$ if we exclude the shortest person of the class whose height is $42 \mathrm{cm}$.