Question
Independent Practice
From 1999 to 2000, the number of days of unhealthy air quality in Charlotte, North Carolina, dropped from 5 to 2. Find the percent of decrease in the number of days of unhealthy air.
A.
15%
B.
1.5%
C.
6%
D.
60%
From 1999 to 2000, the number of days of unhealthy air quality in Charlotte, North Carolina, dropped from 5 to 2. Find the percent of decrease in the number of days of unhealthy air.
A.
15%
B.
1.5%
C.
6%
D.
60%
Answers
GPT-4o mini
To find the percent decrease, we can use the formula:
\[
\text{Percent Decrease} = \frac{\text{Old Value} - \text{New Value}}{\text{Old Value}} \times 100
\]
In this case, the old value (number of days of unhealthy air quality in 1999) is 5, and the new value (in 2000) is 2.
1. Calculate the difference:
\[
\text{Difference} = 5 - 2 = 3
\]
2. Now, use the formula to calculate the percent decrease:
\[
\text{Percent Decrease} = \frac{3}{5} \times 100 = 0.6 \times 100 = 60\%
\]
Thus, the percent decrease in the number of days of unhealthy air quality is:
**D. 60%**
\[
\text{Percent Decrease} = \frac{\text{Old Value} - \text{New Value}}{\text{Old Value}} \times 100
\]
In this case, the old value (number of days of unhealthy air quality in 1999) is 5, and the new value (in 2000) is 2.
1. Calculate the difference:
\[
\text{Difference} = 5 - 2 = 3
\]
2. Now, use the formula to calculate the percent decrease:
\[
\text{Percent Decrease} = \frac{3}{5} \times 100 = 0.6 \times 100 = 60\%
\]
Thus, the percent decrease in the number of days of unhealthy air quality is:
**D. 60%**