Multiples of 15 are: 15,30,45,60,75,90,105,120,135,150,165,180,195,210,225,240,255,270,285,300,315,330,345,360,375,390,405,420,435,450,465,480,495,510,525,540,555,570,585,600,615,630,645,660,675,690,705,720,735,
This means that $51.44 is the discounted price or is equivalent to 80% of the original price, since the 20% equivalent is deducted from the original price.
To get the original price, divide $51.44 by its corresponding percentage, 80%.
$51.44 / 80% = $64.30
To get the discount, multiply the original price by its discount rate
$64.30 x 20% = $12.86
To get the sales price, deduct the discount from the original price.
