Businessman Elon Musk has said people must work up to 100 hours a week to "change the world". Mr Musk works very hard. He is the founder, CEO and lead designer of SpaceX; the co-founder of Tesla; and the co-founder of PayPal. His many projects have changed our lives. He is a workaholic but he loves working. He talked about hard work in an interview. He said: "There are easier places to work, but nobody ever changed the world on 40 hours a week."
Workers at Mr Musk's companies also work long hours. He said "everyone" at Tesla has worked 100 hours per week at times this year. Musk said some Tesla employees were unhappy with their long hours. Others said they like to work 70 hours per week. Musk said, the "pain level" increases above 80 hours a week. He didn't say what the pain was. The average CEO of a multi-billion-dollar company works about 70 hours a week.