SOLUTION: a country's population in 1991 was 147 million. In 1998 it was 153 million what's the population in 2017

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Question 614905: a country's population in 1991 was 147 million. In 1998 it was 153 million what's the population in 2017
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Plot population in millions on the vertical axis, call it +p+
Plot the year on the horizontal axis, call it +t+
Call 1990 0
The slope is:
+%28+153+-+147+%29+%2F+%28+1998+-+1991+%29+=+6%2F7+
The equation so far is:
+p+=+%286%2F7%29%2At+%2B+b+
Plug in the point ( 1, 147 )
+147+=+%286%2F7%29%2A1+%2B+b+
+1029+=+6+%2B+7b+
+7b+=+1023+
+b+=+146.14+
The equation is +p+=+%286%2F7%29%2At+%2B+146.14+
In 2017,
+p+=+%28+6%2F7+%29%2A27+%2B+146.14+
+p+=+23.143+%2B+146.143+
+p+=+169.286+
The population in 2017 will be 169,286,000
check:
The slope should be 6/7
+%28+169.286+-+153+%29+%2F+%28+27+-+8+%29+
+16.286+%2F+19+=+.8572+
+6%2F7+=+.8571+
close enough