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?
Answer & explanation
Correct answer: option 4
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