At a certain food stand, the price of each apple is 40¢ and the price of each orange is 60¢. Mary selects a total of 10 apples and oranges from the food stand, and the average (arithmetic mean) price of the 10 pieces of fruit is 56¢. How many oranges must Mary put back so that the average price of the pieces of fruit that she keeps is 50¢?	Choose the correct choice from the following choices.
A) 2 B) 3 C) 4 D) 5 E) 6

Rationale: "if the average price is 56 , then mary has 8 oranges and 2 apples ( a ratio of 4 : 1 ) . for the average price to be 50 , the ratio should be 1 : 1 . mary must put back 6 oranges . the answer is e ."
Answer: E