Sagot :
Answer:
6%
Explanation:
The marked price of the electric heater = Rs 4000
• In winter, when 10% discount was given, the retailer made 20% profit.
• In summer, ,when the discount was increased by x%,, the retailer made 12% profit.
We want to find the value of x.
First, we find the sale price of the good after a 10% discount.
[tex]\begin{gathered} Sale\;Price=4000-(10\%\text{ of }4000) \\ =4000-400 \\ =\$3600 \end{gathered}[/tex]Next, the retailer made a 20% profit when he sold the heater at $3600, we find the cost price of the heater.
[tex]\begin{gathered} \text{Percentage Profit}=\frac{\text{ Selling Price}-\text{ Cost Price}}{\text{ Cost Price}} \\ \frac{20}{100}=\frac{3600-CP}{CP} \\ 0.2=\frac{3600-CP}{CP} \\ \text{ Cross multiply} \\ 0.2CP=3600-CP \\ CP+0.2CP=3600 \\ 1.2CP=3600 \\ CP=\frac{3600}{1.2} \\ CP=3000 \end{gathered}[/tex]The cost price of the water heater is Rs 3000.
In the summer, she increased the discount percent to get only 12% profit from the same type of heater.
We find the selling price that gives a 12% profit.
[tex]\begin{gathered} \text{Percentage Prof}\imaginaryI\text{t}=\frac{\text{Sell}\imaginaryI\text{ng Pr}\imaginaryI\text{ce}-\text{Cost Pr}\imaginaryI\text{ce}}{\text{Cost Pr}\imaginaryI\text{ce}} \\ \frac{12}{100}=\frac{SP-3000}{3000} \\ \frac{12}{100}\times3000=\frac{SP-3000}{3000}\times3000 \\ 360=SP-3000 \\ SP=3000+360 \\ SP=3,360 \end{gathered}[/tex]The selling price in summer was $3,360.
Finally, we find the discount.
[tex]\begin{gathered} \frac{3360}{4000}=0.84 \\ \implies(1-0.84)\times4000=3360 \\ 0.16\times4000=3360 \end{gathered}[/tex]The new discount was 16%.
Therefore:
[tex]x=16-10=6\%[/tex]The retailer increased the discount by 6%.