A company purchases one of its raw materials from a particular supplier. Purchase details and usage details of this raw material are given below:

$\backslash$table$[[$Maximum lead time,$8$ days$],[$Minimum lead time,$3$ days$],[$Average lead time,$5$ days$],[$Maximum usage,$100kg$ per day$],[$Minimum usage,$60kg$ per day$],[$Average usage,$80kg$ per day$]]$

What is the optimum reorder level for this raw material?

$\backslash$table$[[$A$,[,180kg$