Question 154153
Single women. The percentage of women in the 20–24 age
group who have never married went from 55% in 1970 to
73% in 2000 (Census Bureau, www.census.gov). 
Let 1970 be year 0 and 2000 be year 30.
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a) Find and interpret the slope of the line through the
points (0, 55) and (30, 73).
slope = (73-55)/(30-0) = 0.6
Interpretation: Percentage of women in the 20-24 age group 
who have never married increases by 0.6% each year after 1970.
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b) Find the equation of the line in part (a).
Percent(at year x) = 0.6x + 55 for x >= 1970
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c) What is the meaning of the y-intercept?
In 1970 the percent was 55%
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d) Use the equation to predict the percentage in 2010.
P(40) = 0.6*40 + 55 = 55+24 = 79%
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e) If this trend continues, then in what year will the
percentage of women in the 20–24 age group who have
never married reach 100%?
100 = 0.6x + 55
0.6x = 45
x = 75 years after 1970
1970 + 75 = 2045
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Cheers,
Stan H.