Question

A number is increased by 10% and then it is decreased by 10%. Find the net increase or decrease percent.

Answer 1

Let the number be $100$
Increase in the number $=10$ of $100=\frac{10}{100}\times 100=10$
$\therefore$ Increased number $=100+10=110$
This number is then decreased by $10\%$
Therefore, decrease in the number $=10\%$ of $110=(\frac{10}{100}\times 110)=11$
$\therefore$ New number $=110-11=99$
Thus, net decrease $=100-99=1$
Hence, net percentage decrease $=(\frac{1}{100}\times 100)\%=1\%$