View Full Version : Tell me I'm not crazy (math problem)
Devedander
10-12-2010, 01:39 PM
OK I was helping my friend with a math problem for her homework - this is the problem (109 is the one in question):
http://i.imgur.com/mbEu2.jpg
Now I figured it out and it seemed really simple... but apparently I am wrong... I think the book is wrong... can you guys please figure out the problem and tell me what you come up with so I don't think I am crazy?
BTW book answer: http://i.imgur.com/nzgpj.jpg
ssjmichael
10-12-2010, 01:46 PM
It seems lilke the answers would be 20 and 36 million respectively no? It looks like the solution just tripled the amount of people it could feed, rather than adjusting at the 15 year mark.
edit: errr.. I read the last part wrong. There is no adjusting at the 15 year mark for food production
It's right...$18MM. 6MM*3.
It never said it tripled every 15 years.
Devedander
10-12-2010, 01:50 PM
Tmly can you explain why you chose x3 ?
Curtieson
10-12-2010, 01:50 PM
Now....5 Mil People....6 Mil in Food...
In 30 years....[pop x2 every 15]...so pop = 5x2x2... and food triple = 6x3...
Pop = 20...food = 18
EDIT...check answer....YES!
Tmly can you explain why you chose x3 ?
"the country tripled the amount of food it could produce"
Curtieson
10-12-2010, 01:52 PM
Tmly can you explain why you chose x3 ?
Put the words into math...
In 30 years, the population doubles every 15 and the food increases 3 fold.
We have X = Pop and Y = Food...remove all the info involving X and you have...
In 30 years, the food increases 3 fold.
ssjmichael
10-12-2010, 01:53 PM
It's right...$18MM. 6MM*3.
It never said it tripled every 15 years.
Yeah you're right, it was the wording that threw me off as I thought both were changing every 15 years, but that's just for the population rather than food production.
Fatguy
10-12-2010, 01:55 PM
Well, I'm guessing the difference might be if the food supply triples every fifteen years or just tripled (only once total) that will make the numbers different. The book is correct if you use the food supply tripling only once total (6x3). It seems that the population ends up being 20M total over the entire course of 30 years, so some fools are going to be mighty hungry.
This just reminds me that I'm thankful to be done with school.
looks SAT-Math like.
20Mil Pop
18Mil food
ssjmichael
10-12-2010, 02:03 PM
looks SAT-Math like.
20Mil Pop
18Mil food
It's actually statistical records and projections for Zimbabwe.
It's actually statistical records and projections for Zimbabwe.
shh i channeled my Asian-ness on that one
ASIA POWER!
Devedander
10-12-2010, 02:28 PM
Wow stupid poorly worded math problenms... This is in a section full of exponential growth problems so to put something like that in is just ridiculous!
Thanks for setting me straight though.
What really kills me is that the problem says "30 years ago" then says "after 30 years" does that mean 30 years from now thus a total 60 years grown?
dynamite
10-12-2010, 02:32 PM
The answer is 18 million and the book's answer is correct. The book states the country produced enough food for 6 million people 30 years ago, and over the next 30 years the country was able to triple this food production. 3x6=18. Apparently 2 million people are now cannibals or very very skinny :)
DaddioDan
10-12-2010, 02:33 PM
This just reminds me that I'm thankful to be done with school.
This reminds me how much i hate school.. Stupid biostatistics :mad:
Devedander
10-12-2010, 02:39 PM
This reminds me how much i hate school.. Stupid biostatistics :mad:
Amazingly this is basica algebra... thus my frustration at apparently getting it wrong.
bonkman
10-12-2010, 04:10 PM
This reminds me how much i hate school.. Stupid biostatistics :mad:
biostats is easy. learn a buttload of statistical tests and when to apply each one without any theory or anything. And if you want to be a real biologist, how to bullshit in a paper so people will think you're using the right test even when you have no clue what you're doing :lol:
DaddioDan
10-12-2010, 04:38 PM
biostats is easy. learn a buttload of statistical tests and when to apply each one without any theory or anything. And if you want to be a real biologist, how to bullshit in a paper so people will think you're using the right test even when you have no clue what you're doing :lol:
biostats really is easy, it's just the stupid formulas. My teacher wants me to write out a full equation to find mean, I can't just do (1 + 2 + 3)/3, I have to have sigmas all over the place. And by education I'm already a biologist (BS), in grad school right now for Biomedical Sciences (only MPH), which is something I don't even want to do.:rolleyes:
bonkman
10-12-2010, 05:56 PM
biostats really is easy, it's just the stupid formulas. My teacher wants me to write out a full equation to find mean, I can't just do (1 + 2 + 3)/3, I have to have sigmas all over the place. And by education I'm already a biologist (BS), in grad school right now for Biomedical Sciences (only MPH), which is something I don't even want to do.:rolleyes:
good for you -- best of luck. And two things 1) learn as much math as you can if you're doing anything in the biological sciences. It's something that's often lacking, and it'll let you really critique some papers well. I've read more than a few that only get significant results because they use the wrong tests ie assuming normal distributions when one clearly doesn't exist. Not to mention that math is becoming more and more important (finally) with the rise of bioinformatics and computational biology. 2) Embrace the symbols. It's way easier to write Sigma x(i)/n than (1+2+3+....)/52. Remember, they exist as shorthand, so there's always a way to write something simply.
But what do I know? I quit grad school :lol:
DaddioDan
10-12-2010, 06:06 PM
good for you -- best of luck. And two things 1) learn as much math as you can if you're doing anything in the biological sciences. It's something that's often lacking, and it'll let you really critique some papers well. I've read more than a few that only get significant results because they use the wrong tests ie assuming normal distributions when one clearly doesn't exist. Not to mention that math is becoming more and more important (finally) with the rise of bioinformatics and computational biology. 2) Embrace the symbols. It's way easier to write Sigma x(i)/n than (1+2+3+....)/52. Remember, they exist as shorthand, so there's always a way to write something simply.
But what do I know? I quit grad school :lol:
I'm sure I'll have to do a ton of critiquing, but I'm not sure how much math will be involved. Right now it's all about proteomics and mass spectrometry articles I've been reading. Throw in transgenics and cracinogenesis with a dash of genomics and boy do we have a party. I have no choice but to embrace those damn symbols thanks to my prof, and I'll quit grad school as soon as I get into dental school. Let's just say someone had a little too much fun during his undergrad and his GPA suffered a little bit.:wave: