Allow me to explain MaxWhite's answer(which sounds much closer than just 69890) real fast: (I'm a "mathlete" and no, I haven't done the actual math yet)
EACH ITEM that stocks (NOT three items!) stocks THREE TIMES per hour. Now, I don't know the exact number that's stocking, but it's a good bit. Now then, Subeta tells us that each one of those items is what it says in the question. Take that number, multiply it by the number of items. Then multiply that number by three.
That's how much she /sells/ in an hour.
However, 45% of that is taken by the designers. So multiply how much she sells by .55 and you get your total.
