A student spends $51.93 including tax for an item marked $48.99. what is the percent increase

Sales tax will result an increased priced. Since the increased rate is (1 + x) where x = discount rate. We equate:

$48.99 (1 + x) = $51.93

Solve for x:

1 + x = $51.93/$48.99

x = ($51.93/$48.99) - 1

x = 0.06 or 6%