Nadia Algar is the overworked IT resource person for her department. In the next round of computer purchases, she is determined to recommend a vendor who does a better job of documenting possible errors in the system and whose customer service line is more responsive to the needs of her colleagues. Nadia compiled the following data over an eight$-$week observation period. Assuming $40$ hours per week, what is the system availability for Comtron?

Vendor, No$.$ of problems, Mean time to reach customer service, Mean time to fix

JCN$,50,3,2$

Bell, $100,2,1$

Comtron, $250,1,0\mathrm{.}5$

Answer Choices:

$0\mathrm{.}46$

$0\mathrm{.}52$

$0\mathrm{.}56$

$0\mathrm{.}65$

I chose $0\mathrm{.}56$ which is incorrect. Here is the feedback I received:

Calculate MTBF $=$ time $/$ # falures

Time $=8$ weeks $*40$ hrs per week

Include time to reach customer service in MTTR$.$

Which vendor should Nadia Use? $($JCN$,$ Bell, or Comtron$)$

I chose Comtron which is incorrect.