On Selling a book at 8/15 of the marked price there is a loss of 20 percent. What will be the ratio of marked price and cost price of the book?

3 : 2

             MP               SP

            15                8

Loss = 20% means the selling price is 80% of the cost price

So, 8 = 80% of the cost price

100% of the cost price = 10

MP : CP = 15 : 10 = 3 : 2