By how much percent a shopkeeper must mark his goods above its cost price so as by giving 15% discount, he earns a profit of 2%.

20%

C.P. : MRP = (100 - Discount)% : (100 + Profit)%

                =  (100 - 15)% : (100 + 2)%

                =  85% : 102%

                = 5 : 6                

C.P. = 5R

MRP = 6R

So, shopkeeper marks up his goods by = \(\frac{6R\;-\;5R}{5R}\)× 100%  = 20%