EXERCISE 17.4

A road $90 \mathrm{m}$ long and $10 \mathrm{m}$ wide is to be paved with tiles having length and breadth as $20 \mathrm{cm}$ and $7.5 \mathrm{cm}$ respectively. Find the number of tiles required to pave the road.

A room is $17 \mathrm{m}$ long and $10 \mathrm{m}$ wide. A square carpet of side $10 \mathrm{m}$ is to be laid on its floor. Find the area of the floor which will remain bare.

A paper sheet is $300 \mathrm{cm}$ long and $150 \mathrm{cm}$ wide. Envelopes from small sheets measuring $10 \mathrm{cm}$ and $3 \mathrm{cm}$ have to be made. Find the total number of envelopes that can be made from the big sheet.

The dimensions of a courtyard were measured with a meter stick and hence its area was found to be $400 \mathrm{sq} \mathrm{m}$. Later on it was detected that the length of the meter stick actually measures $90 \mathrm{cm}$ and not one metre. Find the correct area of the courtyard.

Calculate the area (shaded area in figure) of the following figure.

Calculate the area (shaded area in figure) of the following figure.

Calculate the area (shaded area in figure) of the following figure.

The dimensions of a room are $15 \mathrm{m}$ and $10 \mathrm{m}$. Half the area of the room is to be covered with blue tiles and half with white tiles. The length of blue and white tiles is $15 \mathrm{cm}$ and $20 \mathrm{cm}$, respectively and the breadth of blue and white tiles is $10 \mathrm{cm}$ and $15 \mathrm{cm}$ respectively. Find the number of tiles of each colour required to cover the room.