I just need help finding D and E.

Stanleys Secretarial Services uses an average of 1,215 boxes of envelopes each year. Carrying costs per box are $75 per year, and it costs $10 to place and receive an order.

a.	What is the optimal order quantity for boxes of envelopes, to the nearest whole number?

Economic order quantity

boxes

b.	What is the average number of boxes of envelopes in inventory, to the nearest whole number?

Average number of boxes

c.	How times will Stanley order envelopes each year (to the nearest whole number)?

Number of orders per year

d.	Compute the total of ordering and carrying costs for boxes of envelopes. (Round to the nearest whole number, but do not type the dollar sign.)

Total cost

$

e.	Calculate the change in total annual cost, if per-box holding costs went up by $9 per year. (Round your intermediate calculations to 2 decimal places and final answer to 2 decimal places, but do not type the dollar sign.)

Increase by

$