Ok so this is gonna get a little confusing:
So he buys 75 shirts @ $5.30/shirt = $397.50
He has to make $465 above the $397.50 which equals $862.50
That means that to make the amount needed, he would have to sell each shirt @ $11.50/shirt
$5.30/$11.50= .4608695
Meaning that the shirts would have to be marked up roughly 46.09% for Izzy to make the $465 above the cost of the shirts