"How many eggs can you eat in five minutes?"
Translation:Kolik vajíček můžeš sníst za pět minut?
They both mean "to eat". The difference is in the verbal aspect. "Sníst" is perfective (ie. used for one time, finished actions) and "jíst" is imperfective (ie. used for ongoing, repeated, unfinished actions). You might find a more detailed explanation in the tips and notes.
For the above sentence, there is a limited time in which you have to eat as many eggs as you can. After the time runs out the action is finished and you know the outcome, so you have to use the perfective verb (sníst).