Solving for w using Goal Seek???

[alyssa75]

hHere are the knowns:

w * .15 = x
w * .85 = y
y * .15 = z

(x/12)+y+z = value in cell a1 (this is a given, not a calculation)

so with a1 as the known value is there anyway for me to determine the values for x, y and z?

Thanks!

 

[tusharm]

If in x/12+y+z=A1 you replace x, y, and z with the w parameter, you will get a formula like c*w=A1.

This gives w = A1/c. And, from there find x, y, and z using the 3 formulas you already have.

No need for Excel. Paper and pencil will be enough. But, one can also use Excel. {grin}

 

[alyssa75]

Thank you! Can you show me how this would work assuming a1 = 12,000. (Sorry, it's been a while since I've had to do hardcore algebra)

Thanks again!

 

[West Man]

I hope I'm not attempting someone's homework, especially if I get it wrong, but here goes.

a1= (x/12)+y+z so
a1= (x/12)+w
a1= (.15w/12)+w
12*a1=.15w+12w
12*a1=12.15w


w=(12*a1)/12.15
x=.15w
y=1-x
z=.15y

 

[alyssa75]

Not at all...I am a 31yr old Financial Analyst trying to derive the categories (x,y,z) from a single revenue #.

Thanks again!!!

 

[tusharm]

Yes, unfortunately, you did get it wrong

z is in terms of y and not w.

z = 0.15 y
y = 0.85 w

So, z = 0.15*0.85*w

The rest of the well-illustrated algebra should be modified to include the above correction.

I hope I'm not attempting someone's homework, especially if I get it wrong, but here goes.

a1= (x/12)+y+z so
a1= (x/12)+w
a1= (.15w/12)+w
12*a1=.15w+12w
12*a1=12.15w


w=(12*a1)/12.15
x=.15w
y=1-x
z=.15y

 

[alyssa75]

Thanks guys! So using the following worked well using pencil & paper:

x = .15w/12
y = .85w
z = .85w * .15

a1 = (.15w/12) + .85w + (.85w * .15w)

So - using pencil & paper, I can solve this now BUT I want to solve it in excel where A1 is the value in cell A1 and I want x to be returned in A2, y in A3 and z in A4.

 

[alyssa75]

I've seen goal seek used for this sort of thing but it's just not making sense to me..I can't make it work

So first - can someone help me rewrite the above in terms of w (so w= blah blah instead of a1=) and then how can I use goal seek to solve for w.

Thanks much!

 

[tusharm]

There's no need for goal seek. It's useful only if one cannot work out a unique solution using algebra.

In your case, you can rewrite the last equation as
w*(0.15/12+0.85+0.85*0.15) = A1
or
w=A1/(0.15/12+0.85+0.85*0.15)

So, to get w in A2, enter =A1/(0.15/12+0.85+0.85*0.15)

To get x in A3 enter =A2*0.15/12

To get y in A4 and z in A5 enter the appropriate formulas keeping in mind that the value of w is in A2.

Thanks guys! So using the following worked well using pencil & paper:

x = .15w/12
y = .85w
z = .85w * .15

a1 = (.15w/12) + .85w + (.85w * .15w)

So - using pencil & paper, I can solve this now BUT I want to solve it in excel where A1 is the value in cell A1 and I want x to be returned in A2, y in A3 and z in A4.