What is the query equation for qb? Summing the total cost of each purchase order

1)Prepare the following queries, naming the queries qa, qb, qc, etc., according to the identifying letters below. If it takes more than one query to provide the final answer, label each query in order, e.g., qa1, qa2:

a.Use the PO_Items table to calculate the dollar cost of each item purchased on each purchase order (QuantityReceived times Cost); label your new calculated field Purchase Cost. Your query should have the same number of rows as the PO_Items table.

b.Use qa and the PurchaseOrders table to sum the total cost of each purchase order; label your summed field PO Cost.

c.Use qb and the Vendors table to sum the total cost of purchases from each vendor; label your summed field Vendor Purchase Cost.