The eighth season of Shark Tank begins Friday, and one of the show's stars, Mark Cuban, tells Inc. it's going to be "bigger and more intense" than before. Setting the bar for the season in the first episode will be an update on test prep startup Prep Expert, one of Cuban's best-performing investments from the show.

Founder Shaan Patel says he went into the tank in June 2015 confident that his three-year-old business (then called 2400 Expert), which had more than $1 million in revenue and 40 percent margins, would receive an offer from all the sharks--except maybe Kevin O'Leary. Patel had cheekily asked in his pitch video to the producers to exclude O'Leary from the room since he'd never seen him make a great offer. As it turns out, three out of the four sharks present for his pitch (including O'Leary) declined to make an offer, leaving only Cuban on the table.

"I was in the tank for an hour and a half and it felt like 20 minutes," Patel tells Inc. "They really grill you hard." He adds that his uneasiness about potentially leaving without a deal was heightened by the knowledge that only about 30 percent of entrepreneurs who pitch to the sharks are chosen to air on the show, in front of millions of potential customers.

"When they were training us backstage, they were saying that getting 10 minutes of airtime on prime-time television is worth about $9 million in marketing spend," Patel says.

After facing initial doubt about his ability to juggle a business with medical and business school, Patel persuaded Cuban to invest. "By the end of his pitch, I saw his ability to combine brains, dedication, and an entrepreneurial spirit," Cuban tells Inc.

Despite the odds seeming always to be in his favor--Patel is one of 0.02 percent of SAT takers who scored a perfect score--he says success in life comes only through hard work. He learned about work ethic from his father, who immigrated from India with $65 and started running a gas station and a motel while also working as a pharmacist.

"I don't know if I'm taking on as much as my dad," Patel says. "He has been the inspiration for why and how I do all of these things."

Hard work is also a value he shares with his mentor Cuban. "Mark always says, 'There's one thing you can control and that's effort,' and I think that's true," Patel says. "If you are willing to do put in the effort, a lot of good things can happen."

Since Patel appeared on the show, Prep Expert has quadrupled its revenue to more than $4 million, and has grown from 10 employees to 50. This month Patel launched a Kickstarter campaign for his book, How Any Kid Can Start a Business, co-authored by Cuban and 16-year-old-entrepreneur Ian McCue. It is Patel's ninth book--impressive for any 26-year-old, but even more so given that his first was turned down by 100 publishers. But that setback was what that motivated him to start his business and eventually land two book deals with McGraw-Hill prior to going on Shark Tank.

"I think it wouldn't be any fun if there wasn't any struggle," Patel says.