Question 1118462
Initially oranges make up 70% of the total.  So the number of oranges = 0.7*720 = 504
Thus the number of apples = 720 - 504 = 216
Let a = the additional number of apples bought
Then we have 216 + a = 0.4(720 + a), since the new amount of apples is 40% of the new total
Solving for a gives a = 120
So the total number of apples bought is 336