Activity$-$based costing for a service company

$\backslash$table$[[$Activity$,$Activity Rate$],[$Room and meals,$$170$ per day$],[$Radiology$,$$$240$ per image$],[$Pharmacy$,$$$37$ per physician order$],[$Chemistry lab,$$71$ per test$],[$Operating room,$$780$ per operating room hour$]]$

The activity usage information associated with the two patients is as follows:

$\backslash$table$[[,$Abel Putin,Cheryl Umit$],[$Number of days,$4$ days,$9$ days$],[$Number of images,$5$ images,$8$ images$],[$Number of physician orders,$4$ orders,$6$ orders$],[$Number of tests,$3$ tests,$6$ tests$],[$Number of operating room hours,$3\mathrm{.}5$ hours,$6\mathrm{.}5$ hours$]]$

a$.$ Determine the activity cost associated with each patient.

Abel Putin $

Cheryl Umit $

b$.$ Why is the total activity cost different for the two patients?