Help? I don’t understand it

Jabari is power washing houses for a summer job. for every job, he charges an initial fee plus $30 for each hour of work. his total fee for a 4 -hour job, for instance, is $170 . jabari's total fee,f, for a single job is a function of the number,t, of hours it takes him to complete the job. write the function's formula.

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64