Question 251636
The percentage of adult smokers in the U.S. is declining each year. If t represents the number of years since 1997, then
P(t) = -0.51t + 24.675
represents the corresponding percentage of adults who smoked cigarettes during that year.
Write an inequality that can be used to determine the first year in which the percentage of adult smokers falls below 15%.
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Solve the inequality in part a using an algebraic approach. 
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Set P(t) to 15 and solve for t:
P(t) > -0.51t + 24.675
15 > -0.51t + 24.675
15-24.675 > -0.51t
-9.675 > -0.51t
-9.675/(-0.51) < t
18.97 years < t
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That is t is greater than 18.97 years