Question

A number is first increased by 25% and then decreased by 25% find the net increase or decrease percentage

Answer 1

Answer:

decreases by 6.25%

Step-by-step explanation:

let the number be x

after increasing by 25 % it becomes 125x/100

that is 5x/4now decreasing this by 25%

5x/4-25/100(5x/4)

5x/4*3/4

=15x/16

by looking at this number we can say that the number is less than x

by how much is the question so

the effective percentage decreaseis 100-(15/16*100)

100-93.75

6.25%

Answer 2

SOLUTION -

Let the given number be x

Increased number =

⟹ 125% of x

$⟹ \dfrac{125}{100} \times x$

$⟹ \dfrac{5x}{4}$

Decrease number =

⟹ 75% of 5x/4

$⟹ \dfrac{75}{100} \times \dfrac{5x}{4}$

$⟹ \dfrac{15x}{16}$

Net decrease per cent =

$⟹x - \dfrac{15x}{16} = \dfrac{x}{16}$

Net decrease per cent =

$⟹ \dfrac{net \: decrease \: in \: the \: no.}{orignal \: no.} = 100\%$

$⟹ \dfrac{ \frac{x}{16} }{x} \times 100\%$

$⟹ \dfrac{100}{16} \%$

$⟹ \dfrac{25}{4} \%$

⟹ 6.25 %