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 52¢. How many oranges must Mary put back so that the average price of the pieces of fruit that she keeps is 44¢?  Choose the most appropriate option:
A) 1 B) 2 C) 3 D) 4 E) 5

Rationale: if the average price is 52 , then mary has 6 oranges and 4 apples ( a ratio of 3 : 2 ) . for the average price to be 44 , the ratio should be 1 : 4 . mary must put back 5 oranges . the answer is e .
Answer: E