SSC CHSL 7 Jan 2017 Shift 1 Paper

Let list price = Rs. $100\mathit{x}$
After 20% discount, selling price = $\frac{100-20}{100}\times 100\mathit{x}=\mathit{R}\mathit{s}.80\mathit{x}$
Let Cost price = Rs. $\mathit{y}$
⇒ Loss % = $\frac{\mathit{y}-80\mathit{x}}{\mathit{y}}=\frac{16}{100}=\frac{4}{25}$
⇒ 25y -2000x = 4y
⇒ 25y - 4y = 2000x
⇒ y = $\frac{2000\mathit{x}}{21}=95.23\mathit{x}$
If discount = 10%, ⇒ Selling price = $\frac{100-10}{100}\times 100\mathit{x}=\mathit{R}\mathit{s}.90\mathit{x}$
∴ Loss % = $\frac{95.23\mathit{x}-90\mathit{x}}{95.23\mathit{x}}\times 100$
= 5.49 ≈ 5.5%