Y=6/(4*10)-40
y=6/40-40
y=6/0
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It's because a tenth means that you've divided it by 10. So if it's 20, it means you're multiplying tenths by 20, leaving you with 2 wholes.
For example, you have 2 cakes and you cut each into 10 slices, the slices are each one tenth of the whole cake, and in total there are 20 tenths.
Find the slope of the line connecting (1990,435000) and (2005,482300):
482300-435000 47300
m = ----------------------- = ---------------- = 3153/yr (approx)
2005 - 1990 15 yr
Use the point-slope formula to find the equation of this str. line:
y-435000 = (3153/yr)(x-1990)
The year 2020 is 30 years after 1990. Thus, the expected pop in 2020 is
given by y-435000 = 3153(30) = 94590, so that y = 529590.
