(a) Compute the inventory at September 30 on each of the following bases. Assume that perpetual inventory records are kept in units only. Carry unit costs to the nearest cent. (1) First-in, first-out (F1FO). (2) Last-in, first-out (LIFO) (3) Average cost. (b) If the perpetual inventory record is kept in dollars, and costs are computed at the time of each withdrawal, what amount would be shown as ending inventory in (1), (2), and (3) above? Carry average unit costs to four decimal places