Working out a percentage

[Laurens]

I was writing something, and I wanted to emphasise a point by stating the percentage a human lifespan, say 80 years is of 4.6 billion years.

So 80 years would be what percentage of 4600,000,000 years?

Cheers, I fail at maths so any help explaining how to work such a thing out would be handy too

 

[Inferno]

100% = 4,600,000,000
1& = 4,600,000,000 / 100 = 46,000,000
0.000001% = 46

80 / 46 ~ 2, so 0.000002%

Hope I didn't skip a zero somewhere.

EDIT: I totally didn't make a mistake.

 

[Squawk]

100*(80/4600000000)

1.73913043 × 10-6
or
0.00000174%

 

[AdmiralPeacock]

Or you can get even lazier than asking people for the answer and use this online Percent Calculator.

http://www.onlineconversion.com/percentcalc.htm

or this one

http://www.math.com/everyone/calculators/calc_source/percent.htm

80 is what percentage of 4,600,000,000?

0.0000017391304347826088%

0.000002%

 

[Master_Ghost_Knight]

Percent or as the name indicates "per"-"cent" ("for each" "hundred").
Let's say that you take 2 apples out of a basket with 40, how much percentage is that?
Well if you devide 2 by 40 you will get how many apples you have taken for each 1 apple there is in the basket, so to know how much that would be per each 100 apple all you have to do is to multiply that number by 100.
i.e. (part/total)*100= percentage of part of the total

 

[AdmiralPeacock]

Percent or as the name indicates "per"-"cent" ("for each" "hundred").
Let's say that you take 2 apples out of a basket with 40, how much percentage is that?
Well if you devide 2 by 40 you will get how many apples you have taken for each 1 apple there is in the basket, so to know how much that would be per each 100 apple all you have to do is to multiply that number by 100.
i.e. (part/total)*100= percentage of part of the total

or you could use the percentage calculator.

 

[Master_Ghost_Knight]

or you could use the percentage calculator.

And never learn how to do a percentage?

 

[AdmiralPeacock]

or you could use the percentage calculator.

And never learn how to do a percentage?

I was being facetious.

 

[Nelson]

If I may make a suggestion... If you are trying to emphasize the vast difference in those timescales, it may be better to do it with an analogy. For example:

The difference between an 80 year human lifetime, and the 4.6 billion year age of the earth is roughly equivalent to the difference of 0.5 seconds to the span of an entire year. If we condense the entire geological history of the earth down to 1 year, then the average human life amounts to little more than half of a second.

I think this works better, because people generally have an idea about how long a year is, and how long half of a second is. Whenever possible, I try to put ratios like this in terms of quantities that the intended audience would naturally understand.

A little added fact: In this timescale, the renaissance was about 4 seconds ago.

 

[Laurens]

I am slightly peeved by my lack of proper maths tuition, when I was at high school, I was originally put into the foundation maths class (the lowest and most easy paper) - I'm not sure why I was put in low set's for everything, but anyway. The teacher decided I was good enough at the basics of maths to put me in to do the intermediate paper for my GCSE, then he subsequently left, and I didn't get any of the extra tuition that I needed to pass, and thus I ended up with an E in maths.

This kinda severely dented my confidence with my maths skills, and I kinda shun complicated maths these days. I would like to go back and try and learn some of the stuff that I should have learnt at school (the final year was a shambles, and most of my maths lessons were spent messing around cause we always had a substitute teacher - you know how it goes ).

Does anyone know of any good books on maths? I would benefit from one that makes maths interesting in some way, rather than it just being a list of things to remember. I want to see if I can teach myself, and regain some confidence with numbers (then perhaps retake a GCSE for a better grade or something).

Cheers m'dears

 

[lrkun]

If I may make a suggestion... If you are trying to emphasize the vast difference in those timescales, it may be better to do it with an analogy. For example:

The difference between an 80 year human lifetime, and the 4.6 billion year age of the earth is roughly equivalent to the difference of 0.5 seconds to the span of an entire year. If we condense the entire geological history of the earth down to 1 year, then the average human life amounts to little more than half of a second.

I think this works better, because people generally have an idea about how long a year is, and how long half of a second is. Whenever possible, I try to put ratios like this in terms of quantities that the intended audience would naturally understand.

A little added fact: In this timescale, the renaissance was about 4 seconds ago.

Your analogy is briliant. ^^

 

[Inferno]

Laurens, I won't even dignify that question with a response.
Mainly because it would make me look like an even greater nerd than anyone on here. :lol:
(I'll ask a friend, he's studying maths at University...)

 

[nemesiss]

100*(80/4600000000)

1.73913043 × 10-6
or
0.00000174%

the correct term would be :

1.73913043 × 10^(-6) or 1.73913043 × 1/(10^6)

 

[Master_Ghost_Knight]

Does anyone know of any good books on maths? I would benefit from one that makes maths interesting in some way, rather than it just being a list of things to remember. I want to see if I can teach myself, and regain some confidence with numbers (then perhaps retake a GCSE for a better grade or something).

I'm sure that ther are allot of those books but I personaly don't know any of them suited for your requierments. However books that do not show you math in a prescriptive way tend to be very technical and complicated, maybe more than you can handle on your own. (crap even I couldn't handle on my own when I was learning it and I was Ace at math). Something that might be more apropriate for you will have a certain degree of "take my word for it that it works this way", if you want you can ask specific questions and I will be here to expand on them and try to explain why do they work that way, if you want to.

 

[Divergedwoods]

This reminds me of something I worked out a few month ago (apparently I had nothing better to do at the moment)

If we place the entire age of the universe (13.7 billion years) in a 1 meter timeline, The existence of the human species (around 40 thousand years) would be about the size of a single bacteria, and the average lifespan of a human would be equal to the length of 16 base pairs in our DNA

 

[)O( Hytegia )O(]

(80 / 4600,000,000) = (x / 100)
x = 8000 / 4,600,000,000
x = 1.7391304347826086956521739130435e-6
x = ~ 0.00000017391304347826086956521739130435%

Lern2math

 

[Deleted member 619]

I am slightly peeved by my lack of proper maths tuition, when I was at high school, I was originally put into the foundation maths class (the lowest and most easy paper) - I'm not sure why I was put in low set's for everything, but anyway. The teacher decided I was good enough at the basics of maths to put me in to do the intermediate paper for my GCSE, then he subsequently left, and I didn't get any of the extra tuition that I needed to pass, and thus I ended up with an E in maths.

This kinda severely dented my confidence with my maths skills, and I kinda shun complicated maths these days. I would like to go back and try and learn some of the stuff that I should have learnt at school (the final year was a shambles, and most of my maths lessons were spent messing around cause we always had a substitute teacher - you know how it goes ).

Does anyone know of any good books on maths? I would benefit from one that makes maths interesting in some way, rather than it just being a list of things to remember. I want to see if I can teach myself, and regain some confidence with numbers (then perhaps retake a GCSE for a better grade or something).

Cheers m'dears

http://www.amazon.co.uk/Foundations-Mathematics-Ian-Stewart/dp/0198531656#reader_0198531656

This is a pretty good book, and is authored by Ian Stewart, who co-authored the Science of the Discworld series with Terry Pratchett and Jack Cohen. You can read the introduction to get a flavour of it.

 

[Master_Ghost_Knight]

http://www.amazon.co.uk/Foundations-Mathematics-Ian-Stewart/dp/0198531656#reader_0198531656

This is a pretty good book, and is authored by Ian Stewart, who co-authored the Science of the Discworld series with Terry Pratchett and Jack Cohen. You can read the introduction to get a flavour of it.

What? That was horrible, it teached very litle to nothing. Shame on you!

 

[)O( Hytegia )O(]

http://www.amazon.co.uk/Foundations-Mathematics-Ian-Stewart/dp/0198531656#reader_0198531656

This is a pretty good book, and is authored by Ian Stewart, who co-authored the Science of the Discworld series with Terry Pratchett and Jack Cohen. You can read the introduction to get a flavour of it.

BLASPHEMY!
:roll:

 

[Deleted member 619]

Which? The Foundations of Mathematics or Science of the Discworld? :?