Question 1139110: Hello,
I need a bit of help with one question:
In the 1980s, the population of a city decreased by 10%. In the 1990s, its population increased by 50%. How does the population of the city at the end of the 1990s compare with its population in 1980? Show your work.
A.
It is 35% higher
B.
It is 60% higher
C.
It is 40% higher
D.
It is 45% higher
Thank you
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! in the 1980's, the population decreased by 10%.
in the 1990's, the population increased by 50%.
if x is the population in 1980, then x - .10 * x = .90 * x is the population in 1990 and .90 * x + .50 * .90 * x = 1.35 * x is the population in 2000.
that looks like the population in 2000 is 35% higher than the population in 1980.
to verify, assume some numbers in 1980 and then go through the drill.
assume the population in 1980 is 1 million.
by 1990, the population lost 10%, so the population in 1990 would be .9 * 1 million = .9 million.
by 2000, the population gained 50%, so the population in 2000 would be .9 million plus .45 million = 1.35 million.
1.35 million minus 1 million is equal to .35 million / 1 million is equal to .35 * 100 is equal to 35% increase from 1980 to 2000.
i'd go with selection A.
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