Question

If a number increased by 30% and then
Decreased by 30% the net increase /decrease percentage will be

Answer 1

Answer:

The number was decreased by 9%.

Step-by-step explanation:

Let the original number be x.

First the number is increased by 30%.

The increased number is $=x\times(1+\frac{30}{100})=1.3x$

Then the number was decreased by 30%.

The new number is:

$New\ number=1.3x\times(1-\frac{30}{100})\\=1.3x\times 0.7\\=0.91x$

The difference between the original and new number is:

Difference = New Number - Original Number

                  $=0.91x-x\\=-0.09x$

The difference is negative. This implies that the number was decreased.

The decrease percentage is:

$Decrease\%=\frac{Decrease}{Orignal\ number}\times 100\\ =\frac{0.09x}{x}\times100\\ =9\%$

Thus, the number was decreased by 9%.