Question

a no. increased by 10% and then the increased no. is decreased by 10% find the net increse or decrease

Answer 1

Suppose the number be 'x'.
The number when increased by 10 % = $x+x\times \frac{10}{100}=x+\frac{x}{10}=\frac{11x}{10}$
Now, according to the parenthesis, $\frac{11x}{10}$ is decreased by 10%
Then, the number = $\frac{11x}{10}-\frac{11x}{10}\times \frac{10}{100}=\frac{11x}{10}-\frac{11x}{100}=\frac{99x}{100}$
So, net value = $\frac{99x}{100}-x=-\frac{x}{100}$
This negative sign shows there is net decrease of 1%.