Nida has 50 chocolates in which some are in 3 filled boxes and 5 pieces are not in a box. Her friend brought 25 pieces of chocolates. If all chocolates must be placed in a box, how many more boxes do they need? Let's think first. Chain of thought:
There are 50 - 5 = 45 chocolates in three boxes. So, each box is filled with 45 / 3 = 15 chocolates. 5 + 25 = 30 chocolates are needed to be placed in boxes. Hence, they needed 30 / 15 = 2 boxes for the 30 chocolates.
Therefore, the answer is 2.