21% of $100 is $21, so simply deduct 21 from 100 and you are left with $79.00
100
It should be $99.80
40% off of 20 dollars = 60% of 20 dollars (100 - 40 = 60) = 20*60/100 = 12 dollars
25 percent of 18 dollars is 18*25/100 = 4.50 dollars So 25% off of 18 dollars is 13.50 dollars
70% off of 110 dollars = 30% of 110 dollars = 110*30/100 = 33 dollars.
30% off of 20 dollars = 70% of 20 dollars = 20*70/100 = 14 dollars.
(395 - ((395/100) * 30))
40% off of 54 dollars = 60% of 54 dollars = 54*60/100 = 32.40 dollars
100 dollars
30% off of 15.00 dollars = (100-30)% of 15 dollars = 70 percent of 15.00 dollars = 15.00*70/100 = 10.50 dollars
$14.00 fourteen dollars
40% off of 112 dollars = 60% of 112 dollars = 112*60/100 = 67.20 dollars