Urgent

find a ∩ b if a = {3, 6, 9, 12} and b = {2, 4, 6, 8, 10, 12}.
{24, 48}
{6, 12}
{2, 3, 4, 6, 8, 9, 10, 12}

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.