Danielle, some thoughts ..

=sum(a2-b2)/(c2-b2)

above can be changed to just:
=(A2-B2)/(C2-B2)

(think the SUM is extraneous)

Then to derive the calc "backwards", using a bit of algebra:

Put in say, A3:
=D3*(C3-B3)+B3

For the same values in C3:D3 of: 10, 60, 0.4
A3 will return: 30

Another way to directly run the calc "backwards" based is to use Goal Seek

Try playing with this feature in this manner:

Select D2, click Tools Goal Seek,
then make the settings in the Goal Seek dialog:

Set cell: D2
To value: 0.7
By changing cell: A2

Click OK, and the Goal Seek Status dialog
will show whether a solution has been found.
Click OK to accept the solution.
--
Max
Singapore
http://savefile.com/projects/236895
xdemechanik
---
"Danielle" wrote:
No... i needed to penetrate 70% of the range. I don't know what that
formula is.


For example:
I have $30.
My range is $10.00 - $60. The formula to find percentage is
A B C
D
1 Have Min Range Max Range
Range penetration
2 $30.00 $10.00 $60.00
=sum(a2-b2)/(c2-b2)

answer is 40%
Which means, $30 penetrates the range by 40%. If the "have" was $60. then
it would penetrate the range by 100%, and if I "have" $10. then I penetrate
the range by 0%

The above scenario, I have the formula to get the answer for column D.
The next scenario, I need the formula to get the answer for colunm A

A B C
D
1 Have Min Range Max Range
Range penetration
2. ???? $10.00 $60.00
70%