A group of scientists studied the invasion of a species in an area and its effect on the population of the native species between years 1 and 3.

[tex]\[
\begin{tabular}{|c|c|}
\hline
\textbf{Year} & \textbf{Population of Native Species} \\
\hline
1 & 7,950 \\
\hline
2 & 3,460 \\
\hline
3 & 1,380 \\
\hline
\end{tabular}
\][/tex]

What is the percentage decrease in the population of native species between:

A. Year 1 and Year 2, and Year 2 and Year 3?

A. 49.6% and 55.3%
B. 56.5% and 60.1%
C. 52.5% and 63.3%
D. 50.4% and 68.9%
E. 54.3% and 67.6%



Answer :

To determine the percentage decrease in the population of the native species from Year 1 to Year 2 and from Year 2 to Year 3, follow these steps:

1. Identify the starting and ending populations for both intervals:
- From Year 1 to Year 2: The population decreases from 7,950 to 3,460.
- From Year 2 to Year 3: The population decreases from 3,460 to 1,380.

2. Calculate the percentage decrease from Year 1 to Year 2:
- The amount of decrease is [tex]\(7,950 - 3,460 = 4,490\)[/tex].
- To find the percentage decrease, use the formula:
[tex]\[ \text{Percentage Decrease} = \left( \frac{\text{Amount of Decrease}}{\text{Starting Population}} \right) \times 100 \][/tex]
Applying this to the data:
[tex]\[ \text{Percentage Decrease from Year 1 to Year 2} = \left( \frac{4,490}{7,950} \right) \times 100 \][/tex]
- Simplifying the division and multiplication:
[tex]\[ \text{Percentage Decrease from Year 1 to Year 2} \approx 56.48\% \][/tex]

3. Calculate the percentage decrease from Year 2 to Year 3:
- The amount of decrease is [tex]\(3,460 - 1,380 = 2,080\)[/tex].
- Using the same percentage decrease formula, apply the data:
[tex]\[ \text{Percentage Decrease from Year 2 to Year 3} = \left( \frac{2,080}{3,460} \right) \times 100 \][/tex]
- Simplifying the division and multiplication:
[tex]\[ \text{Percentage Decrease from Year 2 to Year 3} \approx 60.12\% \][/tex]

Given the calculated values, the correct option is:
[tex]\[ \text{B. } 56.5\% \text{ and } 60.1\% \][/tex]