Question

The cost of an article is first increased by 20$\%$ and then decreased by 30$\%$ , find the percentage change in the cost of the article.

Answer 1

Let the original price be $x$

Then increased to $20\%⟹x+\frac{20}{100}x=\frac{6}{5}x$

Then decreased to $30\%⟹\frac{6}{5}x-\frac{30}{100}\times \frac{6}{5}x=\frac{21}{25}x$

So the net decrease is $x-\frac{21}{25}x=\frac{4}{25}x$

The percentage change is $\frac{\frac{4}{25}x}{x}\times 100=16\%$