SSC CHSL 6 Mar 2018 Shift 3 Paper

Let 10 fans are sold for Rs. 10, i.e. price of 1 fan = Re 1
⇒ Revenue = 10 × 10 = Rs. 100
Price is decreased by 40%, ⇒ New price = $10-\left(\frac{40}{100}\times 10\right)=\mathit{R}\mathit{s}.6$
Similarly, new sales = $10+\left(\frac{50}{100}\times 10\right)=15$
⇒ New revenue = $6\times 15=\mathit{R}\mathit{s}.90$
∴ % decrease in revenue = $\frac{\left(100-90\right)}{100}\times 100=10\%$