The number of marble slabs of size $20\, cm \times 30\, cm$ required to pave the floor of a square room of side $3\, m$ is:

Two cubes,each of $10 \, cm$ edge,are joined end-to-end. Then,the surface area of the resulting cuboid is ...... $cm^2$.

The perimeter of a square is equal to twice the perimeter of a rectangle whose dimensions are: length $8 \, cm$ and breadth $7 \, cm$. What is the circumference of a semicircle whose diameter is equal to the side of the square? (in $cm$) (Rounded off to two decimal places)

In a swimming pool measuring $90\, m$ by $40\, m$,$150$ men take a dip. If the average displacement of water by a man is $8\, m^3$,what will be the rise in water level? (in $cm$)

In the adjacent figure,find the area of the shaded region in $cm^2$. (Use $\pi = 22/7$)

$A$ rectangular park $60 \, m$ long and $40 \, m$ wide has two concrete crossroads running in the middle of the park, and the rest of the park has been used as a lawn. If the area of the lawn is $2109 \, m^2$, then what is the width of the road? (in $m$)