Answer:
$504
Step-by-step explanation:
Step one:
given data
A shirt that cost $420
we are told that the shirt was on a discount sale of 20%, so when the discount is over the price will return to $420, we are then told that the shirt was marked up 20%.
Step two:
Hence the new cost is
=20/100*420+ 420
=0.2*420+420
=84+420
=$504
