The easiest SAT problem to solve was how to cheat on it.

Speaking out for the first time, the Long Island teen who took college-entrance exams for cash told “60 Minutes” that his scandalous scheme couldn’t have been simpler to pull off.

“I would say that between the SAT and ACT, the security is uniformly pathetic,” a cocky Sam Eshaghoff says in a segment to air this Sunday. “In the sense that anybody with half a brain could get away with taking the test for anybody else.”

Now a student at Emory University, Eshaghoff was arrested in September, and the bust set off a national debate on entrance-exam integrity and trained a harsh light on his tony hometown of Great Neck.

To date, 20 people have been arrested at several Long Island schools allegedly for either paying to have the test taken for them or providing the service.

The 19-year-old whiz kid says his bustling business started with a casual proposal from a classmate. “He’s like, ‘Yo, you’re good on your SATs and I’m not. And you know this is possible. How much is it going to take?’ ”

The answer was a cool $2,500. Eshaghoff told “60 Minutes” that he took the tests — both the SAT and the ACT — roughly 20 times for score-starved clients.

“My whole clientele were based on word of mouth and, like, a referral system,” Eshaghoff said. He offered up his SAT wizardry gratis only once, for his then-girlfriend.

With his business booming, Eshaghoff began to feel like he was performing a noble public service rather than a criminal act that would lead him into handcuffs.

“I mean, a kid who has a horrible grade-point average, who no matter how much he studies is gonna totally bomb this test, by giving him an amazing score, I totally give him this . . . new lease on life. He’s gonna go to a totally new college. He’s gonna be bound for a totally new career and a totally new path on life.”

But while Eshaghoff routinely furnished sky-high scores for his clients — usually between 2170 and 2220 — many ended up in colleges that fell short of Ivy caliber.

One batch of busted customers included entrants to noted party schools like Arizona State and the University of Colorado.

Despite the felony raps against him, Eshaghoff will accept a plea deal that will allow him to avoid jail time by again boosting test scores. Only this time he will offer up his counsel to low-income students looking to ace their exams.

In bashing Eshaghoff’s activity, Nassau County DA Kathleen Rice has said he was stealing coveted college-admission spots from deserving students.

But Eshaghoff blew off that accusation. “I feel confident defending the fact that [my clients] getting into the schools that they ended up getting into didn’t really affect other people.”

He did admit to some shame in the negative attention his arrest has brought to his family.

Eshaghoff’s lawyer, Matin Emouna, said his client was uncharacteristically nervous for the “60 Minutes” interview.

“He was nervous because he didn’t know what the questions were going to be,” Emouna said.

“Sam came across as the true person he is,” the attorney continued. “He is just like any other teenager. He has a very bright future ahead of him. He has learned a valuable lesson: the importance of being a law-abiding citizen.”

But while his brush with the law may have dulled his desire to cheat, the opportunity, he said, remains wide open.

Asked if he could pull his stunt off again despite the national uproar and talk of security improvements, Eshaghoff didn’t hesitate.

“Easily,” he said. “Piece of cake. I could do it tomorrow.”