SOLUTION: I am having a hard time using the formulas they provided with the information given. The number of senior citizens (65 and over) in the US in million n years after 1990 can be est

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Question 32811: I am having a hard time using the formulas they provided with the information given.
The number of senior citizens (65 and over) in the US in million n years after 1990 can be estimated by using the formula s= 0.38n+31.2
The percentage of senior citizens living below the poverty level n years after 1990 can be estimated by using the formula p= -0.25n+12.2
a) how many senior citizens were there in 2000?
b) in what year will the percentage of seniors living below the poverty level reach 7%
c)What is the first year in which we can expect both the number of senioirs to be greater than 40 million and fewer than 7% living below the poverty level?
I was trying for a, 0.38(2000)+31.2=
I was also trying for b, -0.25(0.07)+12.2
I am just stumped on c.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
You need to solve 0.38n+31.2>40,000,000
This will give you a range of "n" values.
Then you need to solve -0.25n+12.2<=0.07
Then find the lowest value of "n" that
satisfies both of these conditions.
Cheers,
Stan H.