Question

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, ff, 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.

Answer 1

Answer: $f=30t+50$

Step-by-step explanation:

Given: 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.

For every job, he charges an initial fee plus $30 for each hour of work.

let m be his initial fee.

Then $f=30t+m$.......(1)

Also, his total fee for a 4-hour job, for instance, is $170.

Put t=4 and f=170 in (1), we get

$170=30(4)+m\\\Rightarrow170=120=m\\\Rightarrow\ m=170-120\\\Rightarrow\ m=50$

Now, put m=50 in the (1), we get the function's formula for Jabari's total fee, f as

$f=30t+50$