Step-by-step explanation:
for any question about %, first establish what is 100% or 1%.
out of this you can find any answer.
so, what is 100% here ?
the total income : $315,500 = 100%
1% = 100%/100 = 315,500/100 = $3,155
how many % are $18,316.40 ?
well, as many % as times 1% fits into that amount :
18,316.40 / 3,155 = 5.805515055... ≈ 5.81%
