600 is the total number of apples (adding all numbers in the apples*frequency column). Dividing this by 20, the number of boxes, we get 30 apples as the mean number in a box.
You can use the factors of the volumes 24, 27 and 48: For example: 8 by 3 by 1 is a total volume of 24 or if you know that 4 times 2 is 8: 4 by 2 by 2 and so on