Question 1173499: PLEASE HELP ME !
According the United nations population statistics , the world population grew by 30% between 1990 and 2010 . The world population is 6,895,889 thousands in 2010. Find the world population in 1990
is it Wrong ?
30/100 =0.3
0.3 x 6,895,889 = 2068766.7
I don't know what next
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! population is 6,895,889 in 2010.
population grew 30% between 1990 and 2010.
let x = the population in 1990.
your formula is 1.3 * x = 6,895,889
divide both sides of this equation by 1.3 to get:
x = 6,895,889 / 1.3 = 5,304,530.
that's the population in 1990.
confirm by doing the following:
the population in 1990 is 5,304,530
it grew by 30% from 1990 to 2010.
the population in 2010 will be 5,304,530 + .30 * 5,304,530.
factor out the 5,304,530 to get:
the population in 2010 will be 5,304,530 * (1 + .30)
simplify to get:
the population in 2010 will be 5,304,530 * 1.3 = 6,895,889
since you had to multiply by 1.3 to get from 1990 to 2010, you have to divide by 1.3 go get back to 1990 from 2010.
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