Question

the world population, in august of 2016, was 7 x 10^9. there is only about 7 x 10^7 square kilometers on earth that is habitable for humans. about how many square kilometers of habitable land is there per person on earth? a 1 x 10^(-2) sq km/person b 1 x 10^2 sq km/person c 1 x 10^16 sq km/person d 1.4 x 10^2 sq km/person

Explanation:

Step1: Identify the formula

To find the amount of habitable land per person, we divide the total habitable land area by the world - population. The formula is $\text{Land per person}=\frac{\text{Total habitable land area}}{\text{World population}}$.

Step2: Substitute the given values

The world population is $7\times 10^{9}$ and the total habitable land area is $7\times 10^{7}$ square kilometers. So, $\text{Land per person}=\frac{7\times 10^{7}}{7\times 10^{9}}$.

Step3: Use the rule of exponents $\frac{a^{m}}{a^{n}}=a^{m - n}$

Here, $a = 10$, $m = 7$, and $n = 9$. Also, $\frac{7}{7}=1$. So, $\frac{7\times 10^{7}}{7\times 10^{9}}=1\times10^{7 - 9}=1\times 10^{-2}$.

Answer:

A. $1\times 10^{-2}$ sq km/person