How to reverse this formula?

  • Thread starter Thread starter mumbles
  • Start date Start date
M

mumbles

I want to change this formula. Right now it is a guessing game on how
to get the formula to equate to the ideal value of .28.
..28=(((E5-(B5*1000*1.305/2080))-D5-C5)/(E5))
E5 represents the number I enter to try to to get to .28
B5 is a number that varies all the time, so I enter different numbers
in B5 in an attempt to get to the right value so the formula equates to
..28
D5 and C5 are constants.
What would the formula look like in order to have .28 be within the
formula, so that I can enter any number as B5 and the result is
whatever the number E5 needs to be? In other words, I want E5 to be
the answer, not .28.
 
mumbles said:
I want to change this formula. Right now it is a guessing game on how
to get the formula to equate to the ideal value of .28.
..28=(((E5-(B5*1000*1.305/2080))-D5-C5)/(E5))
E5 represents the number I enter to try to to get to .28
B5 is a number that varies all the time, so I enter different numbers
in B5 in an attempt to get to the right value so the formula equate
to
..28
D5 and C5 are constants.
What would the formula look like in order to have .28 be within the
formula, so that I can enter any number as B5 and the result is
whatever the number E5 needs to be? In other words, I want E5 to be
the answer, not .28.
Click to expand...

B5 = (((.28 - 1)*E5)+C5+D5)/(1000*1.305/2080)

The only difference should be that this function is defined when E5 =
whereas your function above is not.

Scot
 
mumbles said:
I want to change this formula. Right now it is a guessing game on how
to get the formula to equate to the ideal value of .28.
..28=(((E5-(B5*1000*1.305/2080))-D5-C5)/(E5))
E5 represents the number I enter to try to to get to .28
B5 is a number that varies all the time, so I enter different numbers
in B5 in an attempt to get to the right value so the formula equate
to
..28
D5 and C5 are constants.
What would the formula look like in order to have .28 be within the
formula, so that I can enter any number as B5 and the result is
whatever the number E5 needs to be? In other words, I want E5 to be
the answer, not .28.
Click to expand...

Ha, misread it at first, was solving for B5.

I think it should be:

E5 = ((B5*1000*1.305/2080)-D5-C5)/(.28-1)

Scot
 
mumbles said:
I want to change this formula. Right now it is a guessing game on how
to get the formula to equate to the ideal value of .28.
..28=(((E5-(B5*1000*1.305/2080))-D5-C5)/(E5))
E5 represents the number I enter to try to to get to .28
B5 is a number that varies all the time, so I enter different numbers
in B5 in an attempt to get to the right value so the formula equate
to
..28
D5 and C5 are constants.
What would the formula look like in order to have .28 be within the
formula, so that I can enter any number as B5 and the result is
whatever the number E5 needs to be? In other words, I want E5 to be
the answer, not .28.
Click to expand...

Eventually...

anyway.

=((-B5*1000*1.305/2080)-D5-C5)/(.28-1)

Scot
 
Thanks! your first one was correct =(((.28 -
1)*E5)+C5+D5)/(1000*1.305/2080) except that it gives me a negative
 
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