Question

The length of a hall is $18$ m and its width is $13.5$ m. Find the least number of square tiles, each of side $25$ cm, required to cover the floor of the hall, leaving a margin of width $15$ m all around.

Answer 1

Length of hall $=18m=1800$cm

Breadth of hall $=13.5m=1350$cm

Width of margin $=1.5m=150$cm

Now, $EFGH$ is the required area of hall flow to be filled.

Now, length of floor $=1800-(2\times 150)=1500cm$

Breadth of floor $=1350-(2\times 150)=1050cm$

$\therefore$ Area $EFGH=1500\times 1050=1575000{cm}^2$

Area of 1 square tile $=25\times 25=625{cm}^2$

Number of tiles $=\frac{AreaEFGH}{Areaof1tile}=\frac{1575000}{625}=2520$