Question

A number is increased by 40% and then it is decreased by 40% then the net increase or decrease per cent is
16% increase
16% decrease
56% increase
56% decrease

Answer 1

Given :

• A number is increased by 40% and then it is decreased by 40%

To Find :

• The net increase or decrease percent ?

Solution :

☯ Let the number be "100"

➙ 40/100 × 100 = 40

➙ The increased no. is 100 + 40 = 140

Now, this is decreased by 40%

➙ 40/100 × 140

➙ 5600/100 = 56

➙ 84

➙ The number is 140-56 = 84

• Net decease is 100 - 84 = 16

_______________________

Therefore,

The percentage of net decrease is

➙ 16/100 × 100%

➙ 16%

∴ Hence, option B is correct.

______________________

Answer 2

$\large\underline{\boxed{\red{\tt{question : - }}}}$

• A number is increased by 40% and then decrease by 40% then the net increase or decrease percent is...

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To Find :

• increase or decrease percent..

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$\huge{\bf{\pink{\fcolorbox{yellow}{black}{\underline{\color{blue}{answer : - }}}}}}$

$\small\pink\star \: \: \text{let \: the \: no \: be \: 100}$

No. is increased by 40% = (100 + 40% of 100)

$= (100 + \frac{40}{100} \times 100)$

$= (100 + 40)$

$= 140 \small\star$

Now number is decrease by 40%

= (140 − 40% of 140 )

$= (140 - \frac{40}{100} \times 140)$

$= (140 - 56)$

$= 84 \small\star$

so number was 84 .

Now original amount or base = 100 .

Amount of change = 100 - 84 = 16

$decrease \: percent \: = \frac{16}{100} \times 100$

$decrease \: percent \: = 16 \: percent$

hence the net decrease percent is 16%

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So option B is correct which is 16 % decrease.

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