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

Answer: Option D

Alternate solution
Given:
Number is first increased by 40% and then decreased by 25%, again increased by 15% and then decreased by 20%
$$\begin{array}{rl}& \mathbf{Calculation}:\\ & \text{Let the number be }x\\ & \Rightarrow x\times \frac{7}{5}\times \frac{3}{4}\times \frac{23}{20}\times \frac{4}{5}\\ & \Rightarrow x\times \frac{483}{500}\\ & \Rightarrow 0.966x\\ & \Rightarrow 0.966x\text{ is less than }x\\ & \Rightarrow \text{Decrease percent in the number}\\ & =\frac{x-0.966x}{100}\\ & =3.4\%\\ & \therefore \text{Net decrease percent in the number is }3.4\%\end{array}$$