Question

The United States has one of the lowest rates of cell phone usage in the industrialized world, at 85 cell phones per 100 people. (By contrast, Hong Kong has around 140 cell phones per 100 people.) If the U.S. population is about 302 million, what is the order of magnitude of cell phone use in the United States?Group of answer choices10^610^810^710^5

Answer 1

`10^8`

Explanation:

An order of magnitude is an exponential change of plus or minus 1 in the value of a quantity or unit. The term is generally used in conjunction with power-of-10 scientific notation.

Therefore, if for 100 people 85 of them have cell phones, for 302 million:

`\begin{gathered} (85)/(100)=(x)/(302000000) \\ x=(302000000*85)/(100) \\ x=256,700,000 \end{gathered}`

The number written in scientific notation is:

`x=2.567*10^8`

So its order of magnitude 8.