By how much percent a shopkeeper must mark his goods above its cost price so as by giving 13% discount, he earns a profit of 45%.

66.66%

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

                =  (100 - 13)% : (100 + 45)%

                =  87% : 145%

                = 87 : 145

                = 3 : 5

C.P. = 3R

MRP = 5R

So, shopkeeper marks up his goods by = \(\frac{5R\;-\;3R}{3R}\)× 100% = \(\frac{2}{3}\) × 100% = 66.66%