What is the answer, i only have limited time pls help

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.

Explain how you can use the associative property to evaluate (7x50)x4.

Arectangle has a width of 5 cm and a length of 10 cm. if the width is increased by 3, how does the perimeter change?