Example 13 - Chapter 7 Class 7 Comparing Quantities

Transcript

Example 13 Selling price of a toy car is Rs 540. If the profit made by shopkeeper is 20%, what is the cost price of this toy? S.P = Rs 540 C.P = ? Profit percentage = 20% Now, Profit = S.P − C.P Profit = 540 − C.P Also, Profit percentage = 20% 𝑃𝑟𝑜𝑓𝑖𝑡/(𝐶.𝑃) × 100 = 20 (𝟓𝟒𝟎 − 𝑪.𝑷)/(𝑪.𝑷) × 100 = 20 (540 − 𝐶.𝑃)/(𝐶.𝑃) = 20/100 (540 − 𝐶.𝑃)/(𝐶.𝑃) = 2/10 (𝟓𝟒𝟎 − 𝑪.𝑷)/(𝑪.𝑷) = 𝟏/𝟓 Cross Multiplying 5 × (540 − CP) = 1 × CP 2700 – 5 CP = CP 2700 = 6CP 6CP = 2700 CP = 𝟐𝟕𝟎𝟎/𝟔 CP = 900/2 CP = Rs 450 So, Cost Price is Rs 450