Paul Coletti’s four decades playing the viola have taken him around the globe.

He has studied and performed with some of the best musicians in the world. He has composed works, directed music videos and recorded more than 30 CDs. He has played hundreds of concerts on five continents — including this week in Whitefish as a guest musician with Festival Amadeus, Glacier Symphony and Chorale’s weeklong classical music festival.

But Coletti’s career might never have happened if not for a lucky guess.

He was 8 when his class in Edinburgh, Scotland, was given a musical aptitude test. Half the class was eliminated when asked to determine which of two notes on the piano was higher than the other. Those who survived round one were asked to identify an interval the teacher played on the piano.

Students were eliminated one by one as they gave incorrect answers. Coletti, who had no idea what the right answer was, waited to make his guess — a fifth.

“I was one of eight who passed,” he said in an interview in Whitefish this week. “It was sheer luck.”

After a year learning the viola at school, Coletti showed promise on the instrument. His parents couldn’t afford to pay for private lessons, but a local teacher agreed to teach the boy for free.

Coletti took the lessons, but he had no real love for the instrument. He played primarily for his father, a talented guitarist whose 60-hour-a-week factory job kept him from pursuing a musical career.

“I was doing it for him. I knew very well he would have pursued [music] immediately,” Coletti said. “We said, ‘We’ve got to make this happen.’”

It was nearly nine years later before the viola became more than a hobby for Coletti. Yehudi Menuhin, a violinist who was being hailed as the next Niccolo Paganini, came to Edinburgh to teach a master class and play a concert when Coletti was 17.

Coletti’s life changed forever during the concert. It was the first time he could ever remember crying; tears were unacceptable among tough-as-nails Scottish youths.

“I couldn’t hold the tears back,” he said. “I was crying, no matter how much I tried to hold it in.

“For me, it was seeing God, being in the presence of God,” he added. “It was as though God was saying, ‘This is what is possible for you. Do you want to pursue this?’”

There was only one possible answer to that question.

Days later, Coletti got his chance. During the master class — which Coletti only attended because soccer practice was canceled that day — Menuhin announced he was looking for a Scottish youth to study at a music school he recently had founded in Switzerland.

Menuhin’s first choice was a talented violinist, who turned down the spot because she already had been offered a position at the Royal Academy of Music in London. No one else in the class was quite at the level Menuhin was looking for — but the one instrument his orchestra lacked was the viola.

Coletti was the only viola player in the class.

“I got in through the back door,” he said, adding that he didn’t mind at all not being Menuhin’s first choice.

“For me, it was as though I got a chance to go to heaven,” he said. “I was thrilled to bits.”

Upon his arrival in Switzerland, Coletti had his work cut out for him.

“I was the worst by far. By a landslide,” he said. “I found what I needed to do was essentially practice double everyone else.”

So he did. Coletti practiced in every free moment. He practiced through weekends, through vacations, through holidays, realizing this was his one shot.

After a few years, he reached a “surprisingly good level.” He was good enough that Menuhin asked him to accompany him in concerts around the world, including New York. That opened up doors for more concerts, Coletti said.

“I was blessed,” he said simply.

Luck smiled again on Coletti after he moved to New York. He was dating a violin player studying under Dorothy DeLay, whose students included virtuosos Itzhak Perlman and Pinchas Zukerman.

“Everybody who was anybody was coming through the DeLay studio,” Coletti said. “She was going to open doors for you.”

That proved true for Coletti after he and his girlfriend twice played duets for DeLay. DeLay was asked to find four musicians — “and please not four violinists” — for a New York debut.

“The only viola player she knew was me,” Coletti said, laughing. Thanks to his performances with Menuhin, recommending Coletti “was an easy bet for her.”

So with a $250 viola and a $50 bow, Coletti, then 23, played in New York. That performance changed everything.

He was asked to play concerts. He recorded CDs, including the much-praised “English Music for Viola.” An entire career blossomed before him.

When he was 25, Coletti was offered a position as head of strings at the University of Washington in Seattle. There he met John Zoltek, Glacier Symphony and Chorale’s music director, when he and Zoltek recorded a piece together. The two have been friends ever since.

After two years at UW, Coletti returned to New York to teach at the Peabody Institute of the Johns Hopkins University. He spent the next 16 years based in Manhattan, teaching and performing all over the world.

Then, nine years ago, a new position opened on the other side of the country at the Colburn School in Los Angeles. The school is devoted to improving music education — no easy task in a field dominated by centuries of tradition, Coletti said.

“Conservatories are called that because they’re conservative in the way they do things,” he said. “It was good for the 19th century. It’s useless nowadays.”

Although he has taught for many years, Coletti’s first love is performing.

“When you play your own concerts, that’s why you practice all those hours,” he said. “That’s where your greatest growth or your greatest failures come.”

He takes teaching just as seriously, however, and feels great responsibility to pass on what he has learned as an artist to the next generation of musicians, just as great musicians passed on their knowledge to him.

That’s why community outreach programs, such as Festival Amadeus, are important, Coletti said. Events like this benefit budding musicians and the audiences that come to the concerts.

“It’s my turn to volunteer in the world,” he said. “It’s that unconditional love thing we all aspire to. It’s a chance to put that into practice.”

Coletti is teaching at Camp Festival Amadeus this week and will perform Thursday night as part of the “Serenade for Soloists” concert, which will also feature violinist Tim Fain and the Festival Amadeus Strings. The concert begins at 7:30 p.m. in the Whitefish Performing Arts Center.

For ticket information and a complete Festival Amadeus schedule, visit www.gscmusic.org.