In March 2011, EF Public Library purchased a total of 15 new books published in 2010 with a total expenditure of Rs. 4500. Of these books, 13 books were purchased from MN Distributors, while the remaining two were purchased from UV Publishers. It is observed that one-sixth of the average price of all the 15 books purchased is equal to one-fifth of the average price of the 13 books obtained from MN Distributors. Of the two books obtained from UV Publishers, if one-third of the price of one volume is equal to one-half of the price of the other, then the price of the two books are:

Let 'x' and 'y' be the average price of 13 books obtained from MN Distributors and remaining 2 books purchased from UV Publishers respectively. 

It is given that he spent a total of Rs. 4500. Therefore, 

13x + 2y = 4500 ... (1) 

It is also observed that one-sixth of the average price of all the 15 books purchased is equal to one-fifth of the average price of the 13 books obtained from MN Distributors.

$$\dfrac{4500/15}{6} = \dfrac{x}{5}$$

$$x = 250$$ ... (2)

Form equation (1) and (2) we can say that 2y = 1250.

Let 'a' and 'b' be the price of two books purchased from UV Publishers. It is given that one-third of the price of one volume is equal to one-half of the price of the other.

Therefore, $$\dfrac{a}{3} = \dfrac{b}{2}$$ ... (3) 

Also, $$2y = 1250 = a + b$$ ... (4)

From, equation (3) and (4) we can say that a = 750 and b = 500. Hence, option C is the correct answer.