Markup is the amount a certain seller is adding to the cost to get the selling price of her product. In this problem, Camille Keegan has the selling price of $92.10 and the cost is $62.00. To get the markup, you just have to deduct the cost from the selling price:
$92.10 - $62.00 = $30.10
To get the percent markup, you just have to divide the markup by the cost of the product:
$30.10/$62.00 = 48.55% markup