Capital per person decreases if the rate of net investment (growth rate of capital) :

Let capital per person be k = K / L, where K is the capital stock and L is the population. - The percentage growth rate of capital per person is given by (dk/dt)/k = (dK/dt)/K - (dL/dt)/L = g_K - n, where g_K is the rate of net investment (growth rate of the capital stock) and n is the population growth rate. - Therefore, capital per person decreases (dk/dt < 0) whenever the rate of net investment (growth rate of capital) is less than the population growth rate . - A growth rate of capital that exceeds the population growth rate increases capital per person, while “exceeds savings per person” and “is less than savings per person” are incorrect because comparing investment with savings does not determine whether capital grows faster or slower than population. Thus, “is less than the population growth rate” is the correct answer.