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#1 2005-09-20 04:06:51

jhp
Member
Registered: 2005-09-20
Posts: 2

Find formula?

Hi,

I have one problem and I don´t know can this be solved?
What is the formula of this mathematical problem:
This is like golf handicap 54 is worst and 0 great.
54-0. So if X goes higher solution gets lower.

If values are these

X=1712*60%
Y=56*30%
Z=21*10%
Solution for these numbers=21,4

another example for different numbers for same formula problem:

X=1112*60%
Y=36*30%
Z=22*10%
Solution for these numbers=35,7

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#2 2005-09-20 08:58:38

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Find formula?

Could you reformulate the question?

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#3 2005-09-20 09:40:25

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,552

Re: Find formula?

What you are talking about is an "inverse relationship".

For Example, if 54 was the worst and is worth 0% and 0 is the best and is worth 100% you could have:

x = 0% to 100%
y = 54 to 0

x = (54-y)/54

So, if y=10, then x=(54-10)/54 = 81.5%
Or, if y=50, then x=(54-50)/54 = 7.4%

But there are different solutions that acheive a similar result. In the case I just showed you there is a straight line between the values, ie linear. But maybe you have a curve or something in between. As kyle said, you can give us more data if you want.

(I understand that when you write "21,4" it means "21.4" in the UK/US am I right?)


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#4 2005-09-20 17:12:13

jhp
Member
Registered: 2005-09-20
Posts: 2

Re: Find formula?

Hi,
Yes I mean 21,4 is same as 21.4.

These X, Y and Z values have different importance to result (X=60%, y=30%, Z=10%)
Now I´m missing the formula. I know numbers and final result. Both of these cases uses same formula. I know that it has something to do with golf handicap calculation. If X value gets higher then Result gets smaller. Can this be solved using these numbers?

case1
X=1712 x 60%
Y=56 x 30%
Z=21 x 10%
Result=21.4

case2
X=1112 x 60%
Y=36 x 30%
Z=22 x 10%
Result=35.7

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#5 2005-09-20 20:03:24

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,552

Re: Find formula?

There aren't enough equations to solve it, I think, but ...

If you just combine the numbers: 

1712 x 60% + 56 x 30% + 21 x 10% = 1027.2 + 16.8 + 2.1 = 1046.1
1112 x 60% + 36 x 30% + 22 x 10% = 667.2 + 10.8 + 2.2 = 680.2

Then we could have:

f(x) = y
f(1046.1) = 21.4
f(680.2) = 35.7

The function f(x) in this case could be: 35.7 - (x-680.2)*(14.3/365.9)

So, when x = 1046.1, then y = 35.7 - (1046.1-680.2)*365.9 = 35.7 - (1046.1-680.2)*(14.3/365.9) = 35.7 - 14.3 = 21.4
And, when x = 680.2, then y = 35.7 - (680.2-680.2)*365.9 = 35.7 - 0 = 35.7

But I don't know how to treat the X, Y and Z separately. If you had a few more equations, we could maybe do a better job.


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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