Answer:
She can fill 2 bags for her lunch and will have 1/10 pound left.
Step-by-step explanation:
It is easier if there is a common denominator, so I made the 2/5 into 4/10, so it is the same as 9/10 pound she bought.
4/10 is one bag, and if you double that, it is 8/10 pounds used. This is two bags of raisins for her lunch.
9/10 - 8/10 leaves 1/10 pound remaining, and not in a bag.