please help ..

The following table lists the components needed to assemble an end item, lead times (in weeks), and quantities on hand. Click here for the Excel Data File a. If 43 units of the end item are to be assembled, how many additional units of B are needed? (Hint You don't need to develop an MRP plan,) b. An order for the end item is scheduled to be shipped at the start of week 16 . What is the latest week that the order can be started and still be ready to ship on time? (Hint. You don't need to develop an MRP plan.)