The markup was 20%.
Markup percentage = price difference/original price
First, subtract the new price from the original.
$24 - $20 = $4
Second, divide the price difference by the original price.
$4/$20 = .20
Turn decimal into percentage by moving it to the right twice or multiplying by 100.
.20*100 = 20%
You can check it by multiplying the original cost by 20% then adding it to the original cost.
20*.20 = $4 , 20+4 = $24 (current price)
