A number is first increased by 40% and then decreased by 25%, again increased by 15% and then decreased by 20%. What is the net increase/decrease per cent in the number?

3.4% decrease

Let initial number = X

Number is first increased by 40% and then decreased by 25%, again

increased by 15% and then decreased by 20% .

New number = X  × \(\frac{140}{100}\) × \(\frac{75}{100}\) × \(\frac{115}{100}\) × \(\frac{80}{100}\)

New number = X  × \(\frac{7}{5}\) × \(\frac{3}{4}\) × \(\frac{23}{20}\) × \(\frac{4}{5}\)

= X × \(\frac{483}{500}\) = 0.966X

Decreased Percent = \(\frac{X - 0.966X}{X}\) × 100% = 3.4% decrease