Chapter 7.5, Problem 22E

i.

To determine

To compare in which state the percent of change in the area of wetlands is least and maximum from the year $1780\text{s}$ to $1980\text{s}$ .

Answer to Problem 22E

The percent of change in area of wetlands is least in Alaska is about $0.12\%$ , and

The percent of change in area of wetlands is maximum in Florida is about $45.81\%$ .

Explanation of Solution

Given information:

Consider, the table provided in the question,

Area of Wetlands (millions of acres)
State	$1780\text{s}$	$1980\text{s}$
Alaska	$170.2$	$170.0$
Florida	$20.3$	$11.0$
Louisiana	$16.2$	$8.8$
Minnesota	$15.1$	$8.7$

In Alaska, area of wetlands decreases from $170.2$ millions of acres to $170.0$ millions of acres.

In Florida, area of wetlands decreases from $20.3$ millions of acres to $11.0$ millions of acres.

In Louisiana, area of wetlands decreases from $16.2$ millions of acres to $8.8$ millions of acres.

In Minnesota, area of wetlands decreases from $15.1$ millions of acres to $8.7$ millions of acres.

All these change in area of wetlands happen from $1780\text{s}$ to $1980\text{s}$ .

Formula used:

  $\text{Percent of change, }p\%=\frac{\text{Amount of increase or decrease}}{\text{Original amount}}$

Calculation:

The decrease in area of wetlands in Alaska $=170.2-170.0=0.2$ millions of acres

Percent of change in area of wetlands in Alaska is:

  $\begin{array}{l}p\%\text{ of Alaska}=\frac{0.2}{170.2}\left[\text{Substitute}\right]\\ p\text{\% of Alaska}\simeq \text{0}\text{.0012}=0.12\%\left[\text{Divide}\text{. Then write decimal as a percent}\right]\end{array}$

The decrease in area of wetlands in Florida $=20.3-11.0=9.3$ millions of acres

Percent of change in area of wetlands in Florida is:

  $\begin{array}{l}p\%\text{ of Florida}=\frac{9.3}{20.3}\left[\text{Substitute}\right]\\ p\%\text{ of Florida}\simeq \text{0}\text{.4581}=\text{45}\text{.81\% }\left[\text{Divide}\text{. Then write decimal as a percent}\right]\end{array}$

The decrease in area of wetlands in Louisiana $=16.2-8.8=7.4$ millions of acres

Percent of change in area of wetlands in Louisiana is:

  $\begin{array}{l}p\%\text{ of Louisiana}=\frac{7.4}{16.2}\left[\text{Substitute}\right]\\ p\%\text{ of Louisiana}\simeq \text{0}\text{.4568}=\text{45}\text{.68\% }\left[\text{Divide}\text{. Then write decimal as a percent}\right]\end{array}$

The decrease in area of wetlands in Minnesota $=15.1-8.7=6.4$ millions of acres

Percent of change in area of wetlands in Minnesota is:

  $\begin{array}{l}p\%\text{ of Minnesota}=\frac{6.4}{15.1}\left[\text{Substitute}\right]\\ p\%\text{ of Minnesota}\simeq \text{0}\text{.4238}=\text{42}\text{.38\% }\left[\text{Divide}\text{. Then write decimal as a percent}\right]\end{array}$

Conclusion:

Hence,

The percent of change in area of wetlands is least in Alaska is about $0.12\%$ , and

The percent of change in area of wetlands is maximum in Florida is about $45.81\%$ .

ii.

To determine

To analyze about what percent did the area of wetlands changes from $1780\text{s}$ to $1980\text{s}$ combining of all four states.

Answer to Problem 22E

The percent of change in area of wetlands from $1780\text{s}$ to $1980\text{s}$ altogether in four states is about $10.5\%$ .

Explanation of Solution

Given information:

Consider, the table provided in the question,

Area of Wetlands (millions of acres)
State	$1780\text{s}$	$1980\text{s}$
Alaska	$170.2$	$170.0$
Florida	$20.3$	$11.0$
Louisiana	$16.2$	$8.8$
Minnesota	$15.1$	$8.7$

In Alaska, area of wetlands decreases from $170.2$ millions of acres to $170.0$ millions of acres.

In Florida, area of wetlands decreases from $20.3$ millions of acres to $11.0$ millions of acres.

In Louisiana, area of wetlands decreases from $16.2$ millions of acres to $8.8$ millions of acres.

In Minnesota, area of wetlands decreases from $15.1$ millions of acres to $8.7$ millions of acres.

All these change in area of wetlands happen from $1780\text{s}$ to $1980\text{s}$ .

Formula used:

  $\text{Percent of change},p\%=\frac{\text{Amount of increase or decrease}}{\text{Original amount}}$

Calculation:

The total area of wetlands combining of all the four states in $1780\text{s}$ is:

  $\begin{array}{l}=170.2+20.3+16.2+15.1\\ =221.8\text{ millions of acres }\end{array}$

The total area of wetlands combining of all the four states in $1980\text{s}$ is:

  $\begin{array}{l}=170.0+11.0+8.8+8.7\\ =198.5\text{ millions of acres}\end{array}$

Therefore,

The difference beween the total area of wetlands in $1780\text{s}$ and $1980\text{s}$ is:

  $\begin{array}{l}=221.8-198.5\\ =23.3\text{ millions of acres}\end{array}$

Percent of change in area of wetlands from $1780\text{s}$ to $1980\text{s}$ is:

  $\begin{array}{l}p\%\text{ from }1780\text{s to }1980\text{s}=\frac{23.3}{221.8}\left[\text{Substitute}\right]\\ p\%\text{ from }1780\text{s to }1980\text{s}\simeq \text{0}\text{.1050}=\text{10}\text{.5\% }\left[\text{Divide}\text{. Then write decimal as a percent}\right]\end{array}$

Conclusion:

Hence,

The percent of change in area of wetlands from $1780\text{s}$ to $1980\text{s}$ altogether in four states is about $10.5\%$ .