Work at McDonald or Kmart?

So i just finished my interview at Mcdonalds,and the man said I come back for training monday or tuesday for 3 days and each day 3 hours,BUT i have a interview at Kmart Thursday, My question is if i get the job at Kmart should i take it and leave Mcdonalds, or should i try to work 2 jobs, its very serious i need help