The price of two dozens of oranges is Rs.120/-more than the price of one kg. of mango. The price of one dozen of apple is Rs.80/- more than the price of one kg of mango. Which of the following represents the ratios of the price of one orange and one apple respectively? a) 4 : 5 b) 3 : 2 c) 7 : 9 d) Cannot be determined e) None of these