RQ $23\mathrm{.}2,23\mathrm{.}3$ & $23\mathrm{.}4.$ Oxford Arms sells bullet$-$proof vests through mail

orders. Oxford sells $5,000$ vests per year, with a fixed cost of $$60$ per order,

and a carrying cost of $$15$ per unit average inventory. Oxford's EOQ is $200$

vests. This order quantity implies $\frac{S}{Q}=\frac{5,000}{200}=25$ orders per year and an

ordering cost of $(\frac{S}{Q})F=$$$25(60)=$$$1,500$ per year. Adding the first $15$ units

to the safety stock reduces the expected stockout cost by $$500.$ How much

do Oxford's total costs decrease by adding $15$ units of safety stock?

$$400$

$$225$

$$500$

$$275$