Question

(b) The entire length of Amazon is 4,000 miles.​

Answer 1

Answer.

The total length of the river—as measured from the headwaters of the Ucayali-Apurímac river system in southern Peru—is at least 4,000 miles (6,400 km), which makes it slightly shorter than the Nile River but still the equivalent of the distance from New York City to Rome.

Answer 2

The right answer is 3976.776 miles

But

Approximately it is 4000 miles