Joseph bought two woolen jackets for ₹2,100 and ₹3,150, respectively. By selling the first at a gain of k% and the second at a loss of k%, he found that the selling price of both is the same. What is the value of k?

20

Joseph bought two woolen jackets for ₹2,100 and ₹3,150 respectively.

Selling price = CP ( 1 +- (Loss or Profit)%

So according to the question,

2100 ( 1 + k%) = 3150 ( 1 - k%)

\(\frac{( 1 + k%)}{( 1 - k%)}\)) = \(\frac{3150}{2100 }\) 

\(\frac{( 1 + k%)}{( 1 - k%)}\)) = \(\frac{3}{2}\)

5k = 100

k = 20