Chapter 1.7, Problem 30E

Solution

The percentage increase in U.S. cell phone antennas in that one-year period.

  $71.7\%$

Given:

From December 1996 to December 1997, the number of cell phone antennas in the United States grew from 30,045 to 51,600.

Concept Used:

To calculate the percentage increase:

First: work out the difference (increase) between the two numbers you are comparing.

Then: divide the increase by the original number and multiply the answer by 100. 

% increase = (Increase ÷ Original Number) × 100.

Calculation:

The number of cell phone antennas in the United States grew from 1996 to 1997 is = 30,045 to 51,600.

Total no. of cell phone antennas increase in the United States $=51,600-30,045=21555$

Percentage increase in U.S. cell phone antennas in that one-year period is −

  $\begin{array}{c}=\frac{21555}{30045}\cdot 100\\ =0.717\cdot 100\\ =71.7\%\end{array}$

So the percentage increase in U.S. cell phone antennas in that one-year period $=71.7\%$ .