Delhi Police Constable Exam Model Paper 4

Formula:
If a number increased by x%, then increased number = Actual number × [(100 + x)/100]
Calculation:
Let price of the phone be 100x, then
Price of phone after changes = $100\mathit{x}\times \left[\frac{120}{100}\right]\times \left[\frac{75}{100}\right]\times \left[\frac{125}{100}\right]=\mathit{R}\mathit{s}.112.5\mathit{x}$
Price of phone increased by = 112.5x – 100x = 12.5x
∴ Price of phone increased by = $\left[12.5\frac{\mathit{x}}{100}\mathit{x}\right]\times 100=12.5\%$