Question

4.2 A magazine charges 400 per 10 sq. cm area for advertising. A company decided to order a half-page
advertisement. If each page of the magazine is 12 cm x 20 cm, how much money must the company
pay for it?​

Answer 1

Given :

• Dimensions of page = 12cm × 20cm
• charges of advertisement = 400/cm²

To find :

• Charges for half page advertisement

Solution :

Step 1) Find area of half page

Area of half page = area of page ÷ 2

Area of half page = (12cm×20cm) ÷ 2

Area of half page = 240cm² ÷ 2

Area of half page = 120cm²

Step 2) Find charges of advertisement for half page

Charges of advertisement for 10cm² = 400

Charges of advertisement for 1cm² = 400 ÷ 10

Charges of advertisement for 1cm² = 40

Charges of advertisement for half page ( 120cm²) = 40 × 120

Charges of advertisement for half page ( 120cm²) = 4800

Answer : 4800

Answer 2

Given:

• The magazine charges Rs 400 per 10 sq. cm area for advertising.
• Each page of the magazine is 12 cm × 20 cm.
• The company has decided to order a half-page advertisement.

To find:

• The amount of money the company must pay for the advertisement.

Solution:

The area of each page of the magazine is given by:

$\sf\:Area \:of \:each \:page = Length × Breadth$

$\sf= 12 \: cm \times 20 \: cm$

$\sf= 240 \: c {m}^{2}$

Therefore, the area of a half-page advertisement is:

$\\ \sf \: Area \: of \: half-page \: advertisement = \frac{1}{2} \times Area \: of \: each \: page$

$\\ \sf = \frac{1}{2 } \times 240 \: c {m}^{2} \\ \\ \sf= 120 \: c {m}^{2}$

Now, the magazine charges Rs 400 for 10 sq. cm area of advertising. Therefore, the cost of advertising for 1 sq. cm area is:

$\\ \sf \: Cost \: for \: 1 \: sq. \: cm \: area = Rs \: \frac{400}{10} = Rs \: 40$

So, the cost of advertising for 120 sq. cm area is:

$\\ \sf \: Cost \: for \: 120 \: sq. \: cm \: area = Rs \: 40 \times 120$

$\sf \implies Rs \: 4800$

Hence, the company must pay Rs 4800 for the half-page advertisement.