A tall teenager wearing the olive drab robes of a tribal herdsman came up to me in a small village market.

"You give me 10 rupees (about $1) for this rock," he said in perfect English, thrusting an ordinary-looking green rock at me.

"What kind of rock is it?" I asked. He said he didn't know.

"You give me 10 rupees for the rock," he repeated, sounding more threatening as he adjusted the carbine slung over his shoulder.

"Why should I give you 10 rupees for a worthless rock?" I asked.

"Because," he replied, "you are very rich, and I am very poor."

That was that. My blue jeans and faded shirt didn't fool him. I was an American, and in his mind, all Americans are rich.

You are very rich, and I am very poor. The worlds have an errie simplicty about them. Unfortunately, that's the way much of the Third World looks at the United States.

Seldom is it stated so bluntly. But the feeling is there, nonethless, whether you're talking to a top bureaucrat in Guatemala or a farmer in Tanzania.

America. Through the evyes of the Third World, the land of the Kojak and Robert Redford. Hollywood and Wall Street. Coca Cola, the CIA and three cars in every garage.

A place that despite Vietnam and Richard Nixon is rich and powerful enough to send Peter Frampton records to every corner of the globe, and prop up staggering governments at the same time.

"The United States, my president often says, is the most powerful country the world has ever known since Adam," said Sammy Mdee, press secretary to Tanzanian president Julius Nyerere. "You don't want to cross swords with a country like that unless it is over something very important."

Nyerere, he quickly added, has done so three times.

That, too, is symbolic of how the Third World views the United States. America, in its eyes, is no longer as threatening or all-powered as it once was. Small nations like Tanzania have no fear of challenging it in the United Nations or other world councils.

This doesn't mean U.S. influence or the American presence in the Third World has necessarily diminished. America's impact on developmental policies, industry and especially culture is easily seen.

The big American multinational drug firms line that highways leading into Guatemala City. The neon signs downtown advertise Arrow shirts, Revlon lipstick, Gulf Oil and McDonald hamburgers.

The radio stations and discotheques in Dar es Salaam, Karachi and Jakarta play American truck music. The kids wear blue jeans, and go to American movies.

America's influence is hard to escape. A voice, for example, startled me as I walked down an out-of-the-way alley in the ancient city of Jogjakarta, Indonesia.

"Hey man, give me five," it called out. It came from a young boy of about 12.He wore a Detroit Lions T-shirt.

As an American leaving Washington for my first trip abroad, I had anticipated much of this. I also expected to encounter some understandable hostility and anger.

Surprisingly, I found little. I was greeted with curiousity rather than antagonism. As a white journalist, I ran into far less open hostility walking through the slums of Karachi or Jakarta than I have on visits to public house projects in Washington.

People crowded around me.They invited me to share their meals and tea. They wanted to know where I lived, how many children I had, how many cars I owned, and if sex was really as free and easy in the United States as they had heard.

My answers often disappointed them.

They knew far more about my country than I knew about theirs. The detail was surprising. They were fascinated by Richard Nixon and Watergate. They knew about the CIA, The Washington Post, Muhammad Ali and country music.

The United States, most agreed, is a big, rich, dog-eat-dog country, rife with crime and racial discontent. Not a particularly good place to live, but an okay place to visit.

The people I met generally said their attitude toward the United States was more positive today than any time since the Kennedy era.

Jimmy Carter, however, was a mystery to most. Many couldn't identify him by name. Those from the political left were deeply impressed by his human rights stands of last year, but disillusioned with the course of American policy since.Those on the political right were often outraged.

"How can your president talk about human rights?" one former Guatemalan official asked. "How hypocritical can you be when the CIA has been down here for a generation promoting the very kind of activity Carter is complaining about."

But while I ran into little open hostility, it took little probing beneath the surface to uncover a reservoir of resentment - a widespread feeling that the rich nations of the world have exploited the poor nations, and owe them a debt that it will take centuries to repay.

The United States, because of its size and its multinational corporations, is the target of much of that resentment.

"What the big bosses in the United States order, that's what happens in Guatemala," a $175-a-day plantation worker told me. "They take carloads of money from here and leave us only the scraps."

An equally strong belief exists in the poor countries of the world that they are at the mercy of forces over which they have no control.

"We're very vulnerable to what happens in the outisde world - particularly the United States," complained Federico Fahsen, a Guatemalan businessman. "If there's inflation, if there's a depression, if there's an oil shortage anywhere in the world, we're the first to feel it. And we feel it longer than you do."

"Our culture is very much dominated by the United States," he continued. "Rock music, long hair, smoking dope - everything that is done in the U.S. - we get it here three years later. We're losing our identity."

American-style capitalism is extremely unpopular among many developing countries, and each of the four nations I visited was struggline to control it.

The driving force leading many of them down the path of socialism, however, was nationalism - not ideology.

I encountered remarkably few signs of Soviet influence in my travels, even through Moscow clearly makes its weight felt in the affairs of many developing nations.

In the countries I visited, the global confrontation was viewed as less a political struggle between American capitalism and Soviet communism than an economic struggle between the world's have and have not nations.

"The United States and the Soviet Union are the two biggest imperialistic countries in the world," a young Tanzanian sociologist declared. "The only difference is that in Russia, there's only one company - the state - to exploit the workers."

No corner of the globe, no matter how remote or vermin-infested, has escaped discovery by one group of Americans - the do-gooders.

For decades, the desolate mountains and jungles of the Third World have swallowed up legions of these fervent, tireless souls, determined to do unto others.

And, oh, has the Third World been done unto. It has been saved by missionaries from Iowa, healed by young doctors from Michigan, analyzed by scholars from Cambridge, and taught by Peace Corps volunteers from Connecticut - all committed to saving the developing world from itself.

The latest, and best financed, wave of do-gooders are called "the experts." Their degrees are in engineering and animal husbandry rather than Biblical history. They peddle economic development rather than salvation.

The experts the Pakistani government called in to draw its economic development plans in the 1960s were known as "the harvard group." The planners that Indonesian President Suharto brought into his "New Order" government were called the "Berkeley Mafia."

The result, understandably, is a strong American influence on Third World economic development policies.

"The advisers wanted to develop Pakistan in their own image," said M.A. hussein Mullick, a development specialist at Quaid-i-azam University.

Even when U.S. experts are not involved directly, the Western influence is still there.

"It's very difficult for countries to come up with fresh approaches to economic development," remarked a Scandinavian expert. "Many of the emerging leaders have been educated in the same schools as we have. They read the same books. They go to the same seminars. We - I mean the West - have set the terms and framework of discussion."

Washington's approach to Third World development in the 1960s was based on a concept that became known as the "trickle down" theory.

The idea was that if you spent a lot of money shoring up the "infra-structure" of developing countries - building roads, dams and electric power lines - the benefits would "trickle down" to the people.

They rarely did.

So in 1973, Congress declared infra-structure out, and human needs in. Henceforth, all AID programs were to be aimed directly at the "poorest of the poor."

This presented problems.

For one thing, the new direction discriminated against a number of traditional Latin American allies. Haiti alone among Western hemispheric nations falls into the porest category of developing countries.

Beyond that, many countries still desperately needed and wanted roads, dams and power lines. And bluntly stated, some simply didn't want to help the poorest of their poor.

"People are a little bit leery of working with some of these groups," remarked a former Guatemalan official. "They say we need highways. If the U.S. won't give us money for highways, let's go negotiate with someone else."

What do the developing countries want from the United States? There is, of course, no single answer. The needs and desires of the have and have-not nations within the amorphous Third World grouping are quite different, and often even contradictory.

But the wants of the developing countries include:

Money. More direct aid with fewer strings attached. The United Nations has recommended that developed nations commit 7 percent of Gross National Product to assisting developing countries. Only three nations - Sweden, the Netherlands and Norway - have met this goal. The United States' contribution is .26 percent.

Better terms of trade. Poor nations sell low and buy high.

Greater control over the activities of multinational corporations.

Better terms for the introduction of advanced technology. Most Third World countries rely heavily on imported equipment, but they have no control over its cost.

"What we poor nations need is the right to work and a fair return for our labor. We want equity not charity," Tanzanian President Julius Nyerere told a Howard University audience last August. "We want to depend upon our own efforts and to plan on the basis of those efforts."

Meanwhile, a myriad of unanswered - and perhaps unanswerable - questions confront anyone wishing to ponder the future of the Third World.

There is population. Thousands of children are born each day into a world that can't meet even their most basic needs. How can they be offered even the slightest hop that their lives will be any better than those of their parents?

There is food. The treadmill race continues between the booming population and the world food supply. How will farmers, hamstrung by ignorance and tradition, produce enough to feed the hungry millions?

There is money. How should the West respond to demands for a new international economic order?

There is energy. Will the West continue its heavy reliance on oil? Or will alternative methods reduce the dependency of the West on a handful of Third World nations?

There is equality. Will ruling elites be able to continue to cling jealously to their land and power while the vast majority have little or none?

There is politics.What kind of governments will succeed the present generation of Third World leaders?

There is human dignity. Will the global majority continue to be denied what World Bank President Robert McNamara has termed its fundamental right to "a minimum acceptable level of nutrition, health and education?"

What can - and should - be done?

I don't pretend to know. In my two months in the Third World, I saw more snakeoil than solutions. At times, even the questions seemed blurred.

What remains cemented on my mind are the snapshots of the people: the tiny girls begging with outstretched hands; the mothers cooking over open fires; the fathers too proud to admit their poverty; the frustrated young men who couldn't find jobs.

One of them, a 19-year-old Indonesian, mistakenly left a poem on the typewriter of a British professor.

The teenager finished high school a year ago. He had been a bright student, but he couldn't find work. He had tried scores of places. He felt guilty because his 82-year-old grandmother was supporting him by scrubbing the professor's floors.

Now, he was trying to teach himself to type. His poem was an outcry of despair.

My life is like a loney reed.

My mother and father are dead.

I have no job.

I have no money.

I have no skills.

I don't know where to turn.

So I'm like a lonely reed, bending in the wind.

I hope I don't break.