The percentage of obese children, ages 12-19 years, in a certain country has grown dramatically in recent years. The percentage of obese children
P(t)= -0.0135t^2 + 0.705t + 8 (0 ? t ? 20)
where t is measured in years, with t = 0 corresponding to the beginning of 1980.
(a) What percentage of children were obese at the beginning of 1980? At the beginning of 1990? At the beginning of the year 2000?
1980
1990
2000
%
%
%
(b) How fast was the percentage of obese children changing at the beginning of 1987? At the beginning of 1997?
1987
1997
%/yr
%/yr