The difference in tallying of expenses from a day to day and month to month is the consistency. in a day to day basis it is consistent the time for a day is 24 hrs it will not change, so you will really know why the expenses goes up or down/ unlike for a month to month it is inconsistent,, some months have 30, 31 or 28 days in a month.
1. intersection is all the numbers both sets have in common
so 3, ,7 , 13
2. union is all the numbers from both sets so 1, 5, 8, 12, 17
Try this thing which you can find on internet
8.354•11.81=98.66074 pounds
Because the question is asking "about" how much that water weighs, I would round he answer to 99 pounds
