This is a test of logic and attention to instruction detail. The picture shows 7 apples. If you take 2 apples away from 3 apples, you have 1 left, but you also have the 4 apples that were not involved in the subtraction. Therefore the answer is 5 apples.
Otherwise, you would need to subtract the 4 apples first so that you only had 3 apples from which to take the 2. This will be a confusing question to many who will be frustrated at being presented with one query in written form, but another in the picture which they would expect to display a group of 3 apples.
Of course, there is also the physics of the question. To take two apples, the array will change, for the force and balance have been altered.