A greengrocer sells a melon at a profit of 37.5% on the price he pays for it . What is the ratio of the cost price to the selling price plz show working also

Let the cost price of the melon be $ 10. 
So its selling price is $ 10 X ( 100 % + 37.5 % ) = $ 10 X 137.5 % = $ 13.75 
The ratio of the cost price to the selling price = 10 : 13.75 = 8 : 11
Another solution = 
The cost price = 100 % 
The selling price = 137.5 % 
The cost price : the selling price = 100 : 137.5 = 8 : 11