Maths whizz-kid Arjun Rajyagor has been crowned the first winner of the BBC's Junior Apprentice by Alan Sugar.
The 17-year-old A-Level student, from Essex, beat finalists Zoe Plummer, Tim Ankers and Kirsty Cleaver after a final task to market bottled water.
Arjun has won £25,000 - which will be controlled by Lord Sugar - to launch his business career.
Lord Sugar said he had "that natural business flair combined with intelligence" that "you can't learn".
"I know that Arjun is going to become the best at whatever he wants to do and I will be here for support all the way," he added.
Arjun teamed up with Tim to take on Zoe and Kirsty in the final task. The teams were helped by fired candidates.
Tim and Arjun targeted 20-something professionals with their product, called simply A Bottle Of Water, while the girls opted for Drip Drop - aimed at the teenage market.
In the final boardroom scene, Sir Alan told the girls their advert looked "like a mugging on a council estate" and the boys that their product was "very simple, very defined and, quite clearly, I understood the concept".
He concluded that both presentations were "absolutely incredible".
"You are an inspiration," he added.
Arjun, who runs a computer repair business from his home, is completing his A-levels and has an offer to study engineering science at Oxford University.
He will receive his £25,000 prize when he wants to take on a suitable venture.
"It's been an amazing opportunity and I can't believe I'm the first Junior Apprentice," he said.
"Never in my wildest dreams did I believe that I would win when I first sent off that application form," he added, "but now that I have, I couldn't be more elated."