The weights of 4 boxes are 30, 70, 60 and 20 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?
In a row, there are 6 boys between A and B and A being the first boy in row. There are 3 boys between B and C. If there are 12 boys after C, then how many minimum boys are there in the row?