Question

An elastic band which is 72cm long is stretched to 90cm. Find the percentage increase in its length.

Answer 1

Answer:

Percentage change was of 25%

Step-by-step explanation:

Given:

>> Original size = 72cm

>> Increased size = 90cm

To Find:

>> Percentage of change = ?

Procedure:

>> Change in size = Changed size - Original size

>> Change in size = 90cm - 70cm

>> Change in size = 18cm

$\bf \implies percentage \ change = \dfrac{Change \ in \ size}{original \ size } \times 100$

$\bf \implies percentage \ change = \dfrac{18}{72}\times 100$

$\bf \implies percentage \ change = \dfrac{1}{4} \times 100$

$\bf \implies 25 \ \%$

What is the meaning of percentage?

• Percentage is way of expressing quantity on per hundred.

• The term has been attributed to Latin per centum. Centum means 100.

Answer 2

Answer:

• Original = 72 cm
• Stretched = 90 cm
• Percentage Increase = ?

$\underline{\bigstar\:\textsf{According to the given Question :}}$

$:\implies\sf Increase\%=\dfrac{Change}{Original} \times 100\\\\\\:\implies\sf Increase\%=\dfrac{Stretched-Original}{Original} \times 100\\\\\\:\implies\sf Increase\%=\dfrac{90 \:cm - 72\:cm}{72 \:cm} \times 100\\\\\\:\implies\sf Increase\%=\dfrac{18\:cm}{72 \:cm} \times 100\\\\\\:\implies\sf Increase\%= \dfrac{1}{4} \times 100\\\\\\:\implies\underline{\boxed{\sf Increase\%=25\%}}$

⠀

$\therefore\:\underline{\textsf{Percentage Increase in length is \textbf{25\%}}}.$