A manager is going to purchase new processing equipment and must decide on the number of spare parts to order with the new equipment. The spares cost $179 each, and any unused spares will have an expected salvage value of $49 each. The probability of usage can be described by this distribution: Number 0 1 2 3 Probability .05 .60 .20 .15 Click here for the Excel Data File If a part fails and a spare is not available, 2 days will be needed to obtain a replacement and install it. The cost for idle equipment is $640 per day. What quantity of spares should be ordered

service level is 90.78% ( it falls on cumulative probability of  1.00 or 100%)

Therefore the quantity of spares that should be ordered is 3

Step-by-step explanation:

Given that;

spares cost =  $179 each

salvage value = $49 each

distribution of the probability of usage;

Number      Probability        cumulative Probability

0                   0.05                       0.05

1                    0.60                       0.65

2                   0.20                       0.85

3                   0.15                        1.00

Now

the cost of stock-out (underestimation) Cu

= $640 per day × 2 days = $1,280

the cost of excess inventory (overestimation) Co

= Unit cost - salvage value = $179 - $49 = $130

Therefore Service Level = Cu / ( Cu + Co )

we substitute

Service Level = $1,280 / ( $1,280 + $130 )

= $1,280 / $1410

= 0.9078 or 90.78%

so service level is 90.78% ( it falls on cumulative probability of  1.00 0r 100%)

Therefore the quantity of spares that should be ordered is 3

answer:   (s+1)(s+4)

step-by-step explanation:

factor s2+5s+4

s2+5s+4

=(s+1)(s+4)

mr. india