Math problem help


 Topic: Math problem help
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  Posted on December 14, 2012 00:46
hansio
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#1
Okay so I'm waaay past Algebra 2 (in calculus fk me) and somehow I can't manage to do this problem... help me? It's part of this online homework due in 3 hours from now :(

Between 1960 and 1990 the population of
a city decreased by approximately 4% each
year. In 1960 the population was 572789
What was the population in 1993?

Problem itself doesn't make sense because the decrease in population is between those given years =__=
:blink
  Posted on December 14, 2012 00:50
Pein83
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#2
:sad
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Awesome avy by: sasori_basama_If :amused
  Posted on December 14, 2012 01:01
rafael033
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#3
Pein83 wrote:
:sad
aIGZQ.png]
allt acc :cris1234
  Posted on December 14, 2012 01:27
CrimsonKnight
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#4
hansio wrote:
Okay so I'm waaay past Algebra 2 (in calculus fk me) and somehow I can't manage to do this problem... help me? It's part of this online homework due in 3 hours from now :(

Between 1960 and 1990 the population of
a city decreased by approximately 4% each
year. In 1960 the population was 572789
What was the population in 1993?

Problem itself doesn't make sense because the decrease in population is between those given years =__=
you have to find out what the 4 % was of 1960 and keep it going
Removed
  Posted on December 14, 2012 01:30
alrak93
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#5
Actually just make a table with 4% stacking like Use a graph on a calculator and select a table option of some sort hard to explain.
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  Posted on December 14, 2012 01:47
guipe
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#6
Considering that between 1990 and 1993 decreased 4% each year too:

572789 x (1-0,4)^33=
= 26,724.043584

Avatar by sasori_basama_lf
  Posted on December 14, 2012 01:52
CrimsonKnight
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#7
guipe wrote:
Considering that between 1990 and 1993 decreased 4% each year too:

572789 x (1-0,4)^33=
= 26,724.043584
that's what I got too
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  Posted on December 14, 2012 02:08
EvanGrant
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#8
You have to use a stupid decay formula (we just finished this stuff in my pre-calc class).

I believe the formula is A=P(1+r)^t, where "P" is the original amount, "r" is the rate, and "t" is the time.

So, we would have A=572789(1 - 0.04)^33, which equals 148,917.37 (rounded), but since you can't have part of a person, it would be 148,918.

Edit: Guipe is wrong, because in his formula he did 0.4, which is 40%, not 4%. Right formula, he just put the wrong numbers in it.

eyjHWna.gif
  Posted on December 14, 2012 02:15
guipe
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#9
EvanGrant wrote:
You have to use a stupid decay formula (we just finished this stuff in my pre-calc class).

I believe the formula is A=P(1+r)^t, where "P" is the original amount, "r" is the rate, and "t" is the time.

So, we would have A=572789(1 - 0.04)^33, which equals 155,122.26 (rounded), but since you can't have part of a person, it would be 155,123.

Edit: Guipe is wrong, because in his formula he did 0.4, which is 40%, not 4%.

Oh yeah, you are totally right. Posting when sleepy makes you make stupid mistakes.
Avatar by sasori_basama_lf
  Posted on December 14, 2012 02:21
EvanGrant
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#10
guipe wrote:
EvanGrant wrote:
You have to use a stupid decay formula (we just finished this stuff in my pre-calc class).

I believe the formula is A=P(1+r)^t, where "P" is the original amount, "r" is the rate, and "t" is the time.

So, we would have A=572789(1 - 0.04)^33, which equals 155,122.26 (rounded), but since you can't have part of a person, it would be 155,123.

Edit: Guipe is wrong, because in his formula he did 0.4, which is 40%, not 4%.

Oh yeah, you are totally right. Posting when sleepy makes you make stupid mistakes.
Yeah I just realized I messed up putting some of my numbers in my calculator, so I had to edit my post just now. But it should be good now.
eyjHWna.gif
  Posted on December 14, 2012 03:11
hansio
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#11
Thanks EvanGrant you're the best! =D
:blink