If there are 28 balls left, then 9+12+14+18+21+24+25 =139 cannot be divisible by 3.

If there are 25 balls left, then 9+12+14+18+21+24+25 =142 cannot be divisible by 3.

Assuming that there are 24 balls left, then 9+12+14+18+21+24+25 =143 cannot be divisible by 3.

If there are 2 1 balls left, then 9+12+14+16+18+21+24+25 =146 cannot be replaced by 3.

Assuming that there are 18 balls left, then 9+12+14+16+18+21+24+25 =149 cannot be divided into 3.

Assuming there are 16 balls left, then 9+12+14+16+18+21+24+25 =15/kloc.

If there are 14 balls left, then 9+12+14+16+18+21+24+25 =153 can be replaced by 3.

Assuming that there are 12 balls left, then 9+12+14+16+18+21+24+25 =155 cannot be divided into 3.

If there are 9 balls left, then 28+12+14+18+21+24+25 =158 cannot be divisible by 3.