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
A) 2
B) 3
C) 4
D) 5
E) 6
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 6.
<result>E</result>
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¢?