Mariam goes to the grocery store. She buys:

$$ A candy bar which weights $35$g$.$ The candy bar size is $10*20*80$ mm$,$ its package is black, and it costs $5\mathrm{.}25$ QAR.

$$ A bottle of two liters of milk, which costs $14$ QAR and is packed in a transparent bottle.

$$ One kilo of sugar packed in a white package of size $50*100*150$ mm and costs $4\mathrm{.}5$ QAR.

When she reaches the cashier she packs all three items in a bag and the cashier warns her: $$be careful this bag can only carry $3$ kilograms at most. $$

Question: Which of the above information is relevant for Mariam to make an informed decision whether it is wise to keep all the items in the same bag or not? Is there any missing information?