[tex]\longrightarrow \sf 75+ 30(h-1) [/tex]
Given that :-
[tex]\leadsto[/tex]Remaining hours for which the job will last after first hour= (h-1)
Therefore,
Cost for subsequent hours = 30×(h-1)
= 30(h-1)
Total Cost for job = Cost for 1st hour + Cost for subsequent hours
[tex]\quad\quad\quad\quad\quad\quad\quad\quad\boxed{\sf{= 75+30(h-1)}}[/tex]