In a town of 35,638 people, about a quarter of the population is....

eddy2017

eddy2017

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In a town of 35,638 people, about a quarter of the population is under the age of 35. Of those, just over a third attend local K-12 schools. If the number of students in each grade is about the same, how many fourth graders likely reside in the town?
A. Between 300 and 400
B. Fewer than 100
C. More than 400
D. Between 200 and 300

thanks for any tip
 
there are 35,638 people
1/4 is under 35 years
of these under 35 years 1/3 go to k-12 school.
how many 4th graders?.
I'll keep on working on this tomorrow. you all have a good night. thanks for the tutoring.
 
back to the salt mines! :)
there are 35,638 people. 1/4 is under 35 years how many are under 35?
[math]35,638 / 4 =8,909.5[/math] people are under the age of 35
of [math]8,909.5[/math] a third go to k-a12 school, so
[math]8,909.5 / 3 =2969.83[/math]how many 4th graders out of these?
from k to 12 there are 13 grades
so
[math]2969.83 / 13 =228.448461538[/math]as the problem talks about approximate amount or an estimate I would say that approximately 288 4th graders live in town.
 
Eddy

That’s nice systematic thinking. Well done.

This is not a criticism. You are dealing with what are explicitly approximations. People come in whole numbers. So you do not need to calculate the decimals. It is not wrong; it just wastes a bit of time that you might need on a test.

[math]35638 \div 4 \approx 36000 \div 4 = 9000.\\ 9000 \div 3 = 3000.\\ 3000 \div 13 > 2600 \div 13 = 200.\\ 3000 \div 13 < 3900 \div 13 = 300.\\ \therefore \text {D is the right range.}[/math]
Everything you did was correct. But you can learn how to save time on a test with this kind of question that explicitly does not ask for exact answers.
 
JeffM said:
Eddy

That’s nice systematic thinking. Well done.

This is not a criticism. You are dealing with what are explicitly approximations. People come in whole numbers. So you do not need to calculate the decimals. It is not wrong; it just wastes a bit of time that you might need on a test.

[math]35638 \div 4 \approx 36000 \div 4 = 9000.\\ 9000 \div 3 = 3000.\\ 3000 \div 13 > 2600 \div 13 = 200.\\ 3000 \div 13 < 3900 \div 13 = 300.\\ \therefore \text {D is the right range.}[/math]
Everything you did was correct. But you can learn how to save time on a test with this kind of question that explicitly does not ask for exact answers.
Click to expand...
thank you, jeff!!!! .
You are dealing with what are explicitly approximations. People come in whole numbers. So you do not need to calculate the decimals. It is not wrong

believe me when I say I was about to not count them ( because my reasoning went like this: why put a .5 to a human being, can't be) but then I had second thoughts and I did, but you're right.
 
Eddy

A pure mathematician would praise the way you did it because, for good reasons, they postpone any approximation until the very end. But with crude approximations like this, it saves time to work with round numbers.
 
JeffM said:
Eddy

That’s nice systematic thinking. Well done.

This is not a criticism. You are dealing with what are explicitly approximations. People come in whole numbers. So you do not need to calculate the decimals. It is not wrong; it just wastes a bit of time that you might need on a test.

[math]35638 \div 4 \approx 36000 \div 4 = 9000.\\ 9000 \div 3 = 3000.\\ 3000 \div 13 > 2600 \div 13 = 200.\\ 3000 \div 13 < 3900 \div 13 = 300.\\ \therefore \text {D is the right range.}[/math]
Everything you did was correct. But you can learn how to save time on a test with this kind of question that explicitly does not ask for exact answers.
Click to expand...
Yes, taking it to a round figure does save thinking time
Perfect!. I'll keep it in mind.
 
eddy2017 said:
back to the salt mines! :)
there are 35,638 people. 1/4 is under 35 years how many are under 35?
[math]35,638 / 4 =8,909.5[/math] people are under the age of 35
of [math]8,909.5[/math] a third go to k-a12 school, so
[math]8,909.5 / 3 =2969.83[/math]how many 4th graders out of these?
from k to 12 there are 13 grades
so
[math]2969.83 / 13 =228.448461538[/math]as the problem talks about approximate amount or an estimate I would say that approximately 288 4th graders live in town.
Click to expand...
Good work, but haven't you switched from 228 to 288 for some reason?
 
eddy2017 said:
Nope, not that i know of.
my answer back at #3
2969.83/13=228.448461538 ( without the rounding that Jeff used).
Click to expand...
From post #3 (bold face is mine):
as the problem talks about approximate amount or an estimate I would say that approximately 288 4th graders live in town.
Click to expand...
 
eddy2017 said:
back to the salt mines! :)
there are 35,638 people. 1/4 is under 35 years how many are under 35?
[math]35,638 / 4 =8,909.5[/math] people are under the age of 35
of [math]8,909.5[/math] a third go to k-a12 school, so
[math]8,909.5 / 3 =2969.83[/math]how many 4th graders out of these?
from k to 12 there are 13 grades
so
[math]2969.83 / 13 =228.448461538[/math]as the problem talks about approximate amount or an estimate I would say that approximately 288 4th graders live in town.
Click to expand...
Yes, you're correct. I madeca mistake.
It is 228 and not 288
 
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