The word "burnout" isn't in the dictionary of Jack Zhang, co-founder and CEO of fintech company Airwallex. "I never understand that terminology to be honest. I've worked 100 hours a week from [the] age of 16 for 20 plus years," Zhang told CNBC Make It . For Zhang, hard work meant survival. At age 15, he moved away from his hometown of Qingdao, China to Melbourne, Australia alone, to pursue better opportunities. He barely spoke English and stayed with an Australian host family. Shortly after