In the following question, which of the given statement(s) are necessary for determining the answer.

A shopkeeper mixes two different types of rice A and B and sells the mixture at the rate of Rs. 45 per kg. What is the profit earned by him ?

I. Cost price of rice A is Rs. 42 per kg.

II. Cost price of rice B is Rs. 50 per kg.

III. Cost price of rice B is Rs. 8 per kg higher than that of rice A.