In a certain code, 'book is big' is written as 756; 'big is story' is 764 and 'story book is interesting' is 4356. Which digit represents 'interesting'?
The weights of 4 boxes are 100, 90, 80 and 40 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?