Question

Question 38

In the above question, how many square metres of cloth is required to cover all the display boards? What will be the length in metre of the cloth used, if its breadth is 120 cm?

Answer 1

Given, total display boards = 24

Length of display board = 1m + 50 cm

= 1m + $\frac{50}{100}$m = 1m + $\frac{1}{2}$m [$\because$1 m = 100 cm]

= $\left(\frac{2+1}{2}\right)$m

= $\frac{3}{2}$m

Breadth of display board = 1 m

Now, area of one display board = Length$\times$Breadth

= 1$\times \frac{3}{2}=\frac{3}{2}sqm$

$\therefore$ Area of 24 display boards = 24$\times$Area of one board = 24 $\times \frac{3}{2}$

= 36 sq m

Hence, 36 sq m cloth is required to cover all the display boards.

Now, breadth = 120 cm [given]

$\therefore$ 1 m = 100 cm

$\therefore$ 1 cm = $\frac{1}{100}$m

$\Rightarrow$ 120 cm = $\frac{120}{100}=\frac{6}{5}$m

Let length =$l$ m

$\therefore$ Area of display board = Length $\times$Breadth

36 =$l\times \frac{6}{5}$

$\Rightarrow \frac{36\times 5}{6}=l\times \frac{6}{5}\times \frac{5}{6}$ $\left[\text{multiply both sides by}\frac{5}{6}\right]$

$\Rightarrow$$l$= 30 m