The first Job has a 100% chance for Mark to earn $50,000.
While the second Job Has a possible 50% chance for Mark to earn $20,000 and another possible 50% chance for him to earn $80,000 ($20,000 + $60,000)
If mark is risk neutral (Meaning that he is insensitive as regards to risk taking) and he wants to maximize his expected utility then Mark will go for the 100% chance of earning $50,000.