SOLUTION: In 1991, the life expectancy of males in a certain country was 68.5 years. In 1996 it was 71.1 years. Let E represent life expectancy in year t and let t represent the number of ye

Question 143894: In 1991, the life expectancy of males in a certain country was 68.5 years. In 1996 it was 71.1 years. Let E represent life expectancy in year t and let t represent the number of years since 1991.
The linear function E(t) that fits the data is
E(t)=?t + ?
Use the function to predict the life expectancy of males in 2009?
E(18)=?
Can someone help me with this one I do not understand. I dont understand the year t and let t represent the number of years. Doesnt t already represent a certain year, then it says it is the number of years since 1991? HELP!!!
Answer by oscargut(2103) (Show Source): You can put this solution on YOUR website!
E(t)=at+b , we have to find a and b (real numbers)
In 1991, the life expectancy of males in a certain country was 68.5 years.
t represent the number of years since 1991.
then E(0)=68.5 then b=68.5
then
E(t)=at+68.5
Using now:In 1996 it was 71.1 years
E(5)=a5+68.5=71.1 then 5a=2.6 then a=0.52
then E(t)=0.52t+68.5
RELATED QUESTIONS
In 1992, the life expectancy of males in a certain country was 66.4 years. In 1996, it... (answered by stanbon)

In 1990, the life expectancy of males in a certain country was 62.1 years,1996 it was... (answered by stanbon)

in 1992, life expectancy of males in a certain country was 65.1 years. in 1996, it was... (answered by josmiceli)

In 1991, the life expectancy of males in a certain country was 61.5 years. In 1995, it... (answered by josmiceli)

Please help! I have this story problem: In 1991, the life expectancy for males in a... (answered by rwm)

I have this story problem: In 1991, the life expectancy for males in a certain country... (answered by stanbon)

Please help. In 1991, the life expectancy of males in a certain country was 70.3 years.... (answered by Mathtut)

In 1995, the life expectancy of males in a certain country was 72.3 years. In 2001, it... (answered by stanbon)

in 1992 the life expectancy of males in a certain country was 72.1 years. In 1997 it was... (answered by ankor@dixie-net.com)