# The graph shows the percentage of high school seniors who used alcohol or marijuana during the 30 days prior to being surveyed.

The graph shows the percentage of high school seniors who used alcohol or marijuana during the 30 days prior to being surveyed. The data can be described by the following mathematical models, where n is the number of years after 1980. A is the percentage of seniors using alcohol, and M is the percentage of seniors using marijuana. Alcohol and Marijuana Use by High School Seniors A= -0.8n +81 M= -0.5n+27 80 704 Q Alcohol BO Percentage 50- 40- Marijuana 304 20- 10- 0- 1980 1985 1990 1995 2000 us og Year a. Use the appropriate line graph to determine the percentage of seniors who used marijuana in 2009. % (Type a whole number.) b. Use the appropriate formula to determine the percentage of seniors who used marijuana in 2009. % (Type an integer or a decimal.) Does the formula underestimate or overestimate the actual data shown by the graph? By how much? The formula by %. c. Use the appropriate line graph to estimate the percentage of seniors who used alcohol in 2009. % (Type a whole number.) d. Use the appropriate formula to determine the percentage of seniors who used alcohol in 2009. 1% (Type an integer or a decimal.) How does this compare with the estimate from part (c)? O A. The formula appears to underestimate the percentage, when compared to the line graph. Click to select your answer(s).