Soma has started her own company, Fancy Shawls, which manufactures woven shawls. She rents knitting equipment when necessary. The cost of using the equipment is $$80.$ The rent, electricity and other related costs is $$150.$ The production cost of one shawl is $$7,$ and Soma can sell these for $$16$ each. Construct the model to find the revenue. Define input variables, output variables.

$($a$)$ If Soma sells $52$ shawls, what will her total revenue be$?$

$($b$)$ What will her total variable cost be$?$

$($c$)$ How many shirts must Soma sell to break even?