Kindly explain the solution

Annual sales $=960,000/$store Direct shippingBatch size shipped from each supplier to each store $=40,000$ units Number of shipments$/$yr fromeach supplier to each store $=960,000/40,000=24$ Annual trucking cost for direct network $=24$ x $1,100$ x $4$ x $8=$ $$844,800$ Average inventory at each store for each product $=40,000/2=20,000$ units Annual inventory cost for direct network $=20,000$ x $0\mathrm{.}2$ x $4$ x $8=$ $$128,000$ Total annual cost of direct network $=$ $$844,800+$ $$128,000=$ $$972,800$