Question 384283
In 1990, the life expectancy of females was 78.8 years. In 2001, it was 79.8 years. Let F(t) = life expectancy and t = the number of years since 1990. 
a) Find a linear function that fits the data.
b) Use the function of Part (a) to estimate the life expectancy in 2010.
Show your work not just the final answer. 

F(t) = mt + c
Substituting the first set of figures, F(t) = 78.8 when t = 0 then, 78.8 = (m x 0) + c : c = 78.8
Substituting the second set of figure, F(t) = 79.8 when t = 11 then, 79.8 = 11m + 78.8 : m = 1/11 
a) The linear function: F(t) = t/11 + 78 .8 
b) 2010, t = 20 so, F(t) = 20/11 + 78.8 = 1.82 + 78.8 = 80.62 years 
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OK
cheers,
Stan H.