Each edge of a cube is increased by $50 \%$. Then,the percentage increase in its surface area is (in $\%$)?

The cost of carpeting a room $5 \ m$ wide with carpet at ₹ $3.50$ per $m^2$ is ₹ $105$. The length of the room is ...... $m$.

In the given figure,$ABCD$ is a square. $EFGH$ is a square formed by joining the midpoints of the sides of $ABCD$. $LMNO$ is a square formed by joining the midpoints of the sides of $EFGH$. $A$ circle is inscribed inside $LMNO$. If the area of the circle is $38.5 \text{ cm}^2$,then what is the area (in $\text{cm}^2$) of square $ABCD$?

$A$ solid metallic sphere of radius $21\, cm$ is melted and recast into a cone with diameter of the base as $21\, cm$. What is the height (in $cm$) of the cone?

If a regular hexagon is inscribed in a circle of radius $r,$ then its perimeter is........$r$.

Two roads $XY$ and $YZ$ of $15 \ m$ and $20 \ m$ length respectively are perpendicular to each other. What is the distance between $X$ and $Z$ by the shortest route? (in $m$)