First time playing about with spatial tools for this challenge.
So to start off I joined the two data sets concerned with each individual store. I then used the Create Points tool to mark the points of each store coming out of the join and then another CreatePoints tool to mark each warehouse coming out of that input.
Then the FindNearest tool was implemented with the store points going into the target input and the warehouse points going into the universe input with the maximum distance set at 100,000 miles.
A simple formula to find the total miles was just the Distance in miles each item has to travel to get to the nearest store multiplied by the number of assigned items for that store.
Summarize tool to group by the Item and sum the total miles to calculate the total distance for each item.
Select tool was then used to rename a column to match that of the given output.