hmm
find cost of 6 regular ones
6 times 16.6=99
so
regular-discountedprice=discount
99-90=9
discount is 9
wait, but out of what
that is 6 jobs so
9/6=1.5 discount per job
to find the percent discount
do
discount/original times 100
1.5/16.5 times 100
0.09090909 tims 100
9.090909
so 9% discount