The weights of 4 boxes are 20, 40, 50 and 30 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxesÂ and in a combination a box can be used only once?

The weights of 4 boxes are 20, 40, 50 and 30 kilograms. Which of the f

1.	The weights of 4 boxes are 20, 40, 50 and 30 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxesÂ and in a combination a box can be used only once?
A.	140
B.	130
C.	90
D.	120
Answer» C. 90