Suppose the percent of U.S. high school seniors from 1975 to 2001 who used marijuana can be modeled by percent, where x is the number of years past 1975. Choose the correct interpretation the slope in this equation as a rate of change.
A) The percentage of U.S. high school seniors who used marijuana increased at a rate of 0.177% per year.
B) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 17.7% per year.
C) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 0.177% per year.
D) The percentage of U.S. high school seniors who used marijuana increased at a rate of 17.7% per year.
E) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 1.77% per year.

Question

Suppose the percent of U.S. high school seniors from 1975 to 2001 who used marijuana can be modeled by  percent, where x is the number of years past 1975. Choose the correct interpretation the slope in this equation as a rate of change. ​
A) The percentage of U.S. high school seniors who used marijuana increased at a rate of 0.177% per year. 
B) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 17.7% per year. 
C) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 0.177% per year. 
D) The percentage of U.S. high school seniors who used marijuana increased at a rate of 17.7% per year. 
E) The percentage of U.S. high school seniors who used marijuana decreased at a rate of 1.77% per year.

Quizplus · Accepted Answer

The coefficient 0.177 represents the slope of the line, which means that for each additional year past 1975, the percent of high school seniors using marijuana decreased by 0.177%. Therefore, choice C is the correct interpretation of the slope as a rate of change. Choices A, B, D, and E all provide incorrect interpretations of the slope.

Suppose the Percent of U