Phoebe Gates, the youngest daughter of billionaire Microsoft founder Bill Gates and philanthropist Melinda French Gates, has a low-key terrifying question she throws at those interviewing for a role at her startup. 

The 23-year-old recently raised a $35 million Series A for Phia, the AI shopping agent she cofounded in April 2025 with her Stanford University roommate Sophia Kianni. The startup, which has since garnered more than 1 million users and grown revenue elevenfold, is currently valued at around $185 million. 

Gates recently joined Brian Sozzi, Yahoo Finance executive editor, on the Opening Bid Unfiltered podcast and revealed her go-to interview question for prospective candidates.

“I stole this from another founder,” she said. “‘How much do you think California state spends on healthcare? And do a bottoms-up approach for how you would build that out.’”

Subscribe to the Daily newsletter.Fast Company's trending stories delivered to you every day

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

SIGN UP

Privacy PolicyFast Company Newsletters

She told Sozzi, “I’ll ask that for every single role. I’ll ask that for sales, I’ll ask that for marketing, I’ll ask that for engineering.” 

It’s not because she expects candidates to know the answer off the top of their head. Instead, she said it highlights “how someone goes through a logical approach to solving that question.”

Curveball interview questions, designed to surprise candidates and test problem-solving ability or performance under pressure, are famously beloved by founders. Microsoft apparently posed the question “Why are manhole covers round?” to interviewees. 

© Fast Company