Problema Solution

According to Zipf's Law, the number of cities with a population greater than S is inversely proportional to S. In 2000, there were 48 U.S. cities with a population greater than 350,000. Estimate the number of U.S. cities with a population greater than 200,000.

Answer provided by our tutors

general form for an inverse relationship:

N = k(1/S)


we solve for 'k' with the known facts:

48 = k(1/350000)

k = 48*350000


we solve for 'N' given the new information

N = (48*350000)(1/200000)

N = 84


there are an estimated 84 U.S. cities with a population greater than 200,000