Explanation:
- We're told that in the formula M = -0.4n + 32, n represents the number of years after 1980.
Since want to determine the percentage of seniors who used alcohol in 1995, we subtract 1995 from 1980 to find n:
n = 1995 - 1980
n = 15
Thus, n = 15.
Now, we plug in 15 for n in M = -0.4n + 32 to find the percentage of seniors who used marijuana in 1195 according to the formula:
M = -0.4(15) + 32
M = -6 + 32
M = 26
Therefore, according to the formula, 26% of seniors used marijuana. This is why 26% is the correct answer.