A shopkeeper buys a certain number of pens. If the selling price of 5 pens is equal to the cost price of 7 pens, find his profit or loss percentage.

Question

***[isuru]*** · Answer

if the selling price of 5 pens = 5x
the selling  price of one pen = x

then the cost of 7 pens also = 5x
so the cost of 1 pen = 5x/7

the difference between the selling price and the cost =  x - 5x/7
                                                                             = 2x/7

so the percentage profit  =                                                                                                     (the difference between the selling price and cost / cost price ) x 100%

***[isuru]*** · Answer

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