Step-by-step explanation:
$333 for 18 hours work.
so,
333/18 = $18.50 for a single hour.
how many hours to make $425.50 ?
well, as often as the amount of 1 hour work fits into 425.5 :
425.5 / 18.5 = 23 hours
she will have to work 23 hours to make $425.50.