how to calculate?

**massa56** · 02-23-2009, 05:30 AM

Hi,

I have to solve dilution calculation like that:
1) if I have two results, let's say R1=0.100 (17.7%) and R2=0.465 (82,3%), in current situation the sum is 0.565 (100%)
2) the sum must be smaller then 0.5.
3) I need to reduce R1 (%) automatically (results R1=0.100 and R2 will be the same), so that the sum will be not greater then 0.5
how to do this in excel?
Thanks!

**DonkeyOte** · 02-23-2009, 05:31 AM

Do you mean:

=MIN(0.5,SUM(R1:R2))

**massa56** · 02-23-2009, 05:40 AM

Thank you DonkeyOte,

no, I need the % of R1 and R2, so that the sum of R1,R2 will be not greater then 0.5
I have to reduce the % of R1, the % of R2 will grow

**Dav** · 02-23-2009, 05:53 AM

r1=0.5-r2

Is this what you mean?

Regards

Dav

**massa56** · 02-23-2009, 05:59 AM

No Dav,
the question is how big must be the dilution of R1 (in %), that the sum of R1 and R2 will be smaller then 0.5

**gdfiler** · 02-23-2009, 06:34 AM

If the values are stored in column R and the % in column S, then I think this is the formula you need.

=(0.5-R2)/((R1/S1)*100)

Don't forget to format it into %

G.

**massa56** · 02-23-2009, 06:41 AM

Hi gdfiler,

the value S1 is unknown

Regards

**gdfiler** · 02-23-2009, 07:15 AM

When you refer to R1 or R2 are you talking about a cell reference?

For the above to work column R should contain the value, column S should contain the associated percentage.

For example cell R1 = 0.100, cell S1 = 17.7%, cell R2 = 0.465, cell S2 = 82.3%

G.