If the amounts of apples and pears were originally A and P, then A+P=25 fruits in all.
Vivi and Gigi between them eat 4 apples and 5 pears. That's 9 fruits in all, so the basket contains 25-9=16 fruits, half of which are apples and half pears (same amount of each), therefore there are now 8 apples and 8 pears.
The original amount of pears=8+5=13 pears (12 apples).