Rifka's statement can be simplified to the following conditional diagram:
Ask directions - > lost NOT lost - > NOT ask directions (contrapositive)
She then concludes that they do not need to ask for directions, thereby assuming that they are not lost.
Craig rejects this assumption that they are not lost by clearly stating that they are lost. In so doing, he concludes that they need to ask for directions, which is a different conclusion from Rifka.
Don't be too worried if you found this question difficult, it's an unusual question but one that will surely help you down the line.
