I got stuck when I arrived at the question how many oranges should their be in the first place.
If there is some unknown quantity – write it down as a variable. Don't be afraid to use many variables if needed. Some of them might get a fixed value after.
So let's denote the number of oranges by o
and the number of apples by a
. What do we know from the question statement?
What else do we have in the statement? The average price! Write down the equation for the average price of a fruit and you'll have the system of equations to solve.