Need someone to solve this for me...

Sham Squire

If my club has 6 members in 1980 and by 2010 it has 50,000 by what percentage on average has it grown year on year?

I'm afraid I couldn't figure it out as everytime I tried I kept passing out. Thanks.

And just to be clear, this is not homework. I'm 35 and it's for a script I'm writing for a voiceover, I just come over all queasy every time I write the numbers down and look at them. It's bringing me back to my leaving cert days (shudder).

chprt

will work it out when I get home mate and post it ltr


paddy

Fremen

Just over 35% (a closer figure is 35.112%). Feel free to throw me out an assistant scriptwriter credit...

Edit: you can check this on a calculator by pressing

6 =

(a six will appear on screen).

Then press X 1.35112 and you'll see a number close to 9. Now press = twenty nine more times.

monsy

I make it 99.888%

monsy

or thereabouts...

gerry87

monsy wrote: »

I make it 99.888%

That would give the club a good 6.3 billion members.

Sham Squire

Thanks very much for the replies. It's for a documentary on Community Radio but I can defo include a shout out in thanks. What would you like to be referred to as?

Fremen

Nah, don't worry about it. It was just a joke.

bnt

I got 35.11% too - here's the maths I used, where n is the factor of increase per year. You have a constant percentage increase per year, 30 times, so it's raised to the 30th power:
[latex]n^{30}=\frac{50000}{6}[/latex]
[latex] n=8333.3^\frac{1}{30}= 1.35112[/latex]

That's what it's increased to per annum (i.e. it's 135.11% of the previous year); subtract the 1 to get what it increased by.

chprt

24.58% is the real answer folks


paddy

bnt

You're not treating this as a continual exponential function, are you? That would be a mistake, since the question is about year-on-year increases, data points a year apart i.e. it's not a continuous function.

Fremen

chupasart.com wrote: »

24.58% is the real answer folks


paddy

Where did that figure come from?

I solved

[latex] 6(1 + x)^{30} = 50000 [/latex]

for x. I guessed the OP didn't much care about how to set up the equation, so didn't think it was worth posting the details.

LeixlipRed

chupasart.com wrote: »

24.58% is the real answer folks


paddy

Nope, it's not.

chakotha

35.9357%

marglin

i got 35.11% as well, i know someone said they're discrete time points but averaging over 30 years it wont make much difference will it?

stiofan85

35.112%

Hurrah!

chakotha

chakotha wrote: »

35.9357%

Sorry that will give 60000 members, my bad.

I hereby change my entry to 35.11%

c-note

just for future reference if you want to work something like this out again,


you have your starting figure, your % increase, time and end figure
The formula is
(start)*(increase)^(time)=(end) (where * = multipy, ^= power)

in this case:

(6)*(X)^(30)=(50000)
so

(x)^(30)=(50000/6)

then you get the log of each side

log(x^30)=log(50000/6)

here's where the trick is, you can bring the 30 in front of the log! (i know mad!)

30*log(x)=log(50000/6)

log(x)=(log(50000/6))/30

x= 10^(log(50000/6))/30

x=1.35(ish)

so it grew by a factor of 1.35 year on year = 35% increase