If it takes a supplier 25 days to deliver an order once it has been placed and the standard deviation of daily demand is 20, which of the following is the standard deviation of usage during lead time?
a. 50
b. 100
c. 400
d. 1,000
e. 1,600

Xinhong company is considering replacing one of its manufacturing machines. the machine has a book value of $39,000 and a remaining useful life of 5 years, at which time its salvage value will be zero. it has a current market value of $49,000. variable manufacturing costs are $33,300 per year for this machine. information on two alternative replacement machines follows. alternative a alternative b cost $ 115,000 $ 117,000 variable manufacturing costs per year 22,900 10,100 1. calculate the total change in net income if alternative a and b is adopted. 2. should xinhong keep or replace its manufacturing machine