Apoorva Mehta had 20 failed startups before Instacart

The gig: Apoorva Mehta, 30, is the founder and chief executive of San Francisco grocery delivery startup Instacart. Over the last four years, he has grown the company to more than 300 full-time employees and tens of thousands of part-time grocery shoppers. The startup offers on-demand and same-day grocery delivery in hundreds of cities in 20 states.