By how much percent a shopkeeper must mark his goods above its cost price so as by giving 30% discount, he earns a profit of 40%.

100%

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

                =  (100 - 30)% : (100 + 40)%

                =  70% : 140%

                = 7 : 14

                = 1 : 2

C.P. = 1R

MRP = 2R

So, shopkeeper marks up his goods by = \(\frac{2R\;-\;1R}{1R}\)× 100% =  100%