doubling a number X number of times
 

Hello,

I am working on a little spreadsheet that works out the range of fire alarm
speakers. The dBA drops off 6 dBA every time you double the distance from
the speaker. I am confident that I have the number of times that the
distance should be double, but I do not know of a way to translate it to a
formula. Below is a bare bones description of what I believe needs done.

I have a number X, that I would like to double Y number of times. Each time
X is doubled the answer becomes the new X. For example, X=10 and Y=3.25.

1.) 10x2=20
2.) 20x2=40
3.) 40x2=80
[Then to get the .25 part]
4.) 80x2=160

160-80=80x.25=20

Answer: 80+20=100.

Any thoughts on a clever way to do this in excel?

Many Thanks!!

Assuming X in A1, Y in A2,

=(A1*(2^INT(A2)))*(1+MOD(A2,1))

--
HTH

Bob Phillips

"Bob" wrote in message
...
Hello,

I am working on a little spreadsheet that works out the range of fire
alarm
speakers. The dBA drops off 6 dBA every time you double the distance from
the speaker. I am confident that I have the number of times that the
distance should be double, but I do not know of a way to translate it to a
formula. Below is a bare bones description of what I believe needs done.

I have a number X, that I would like to double Y number of times. Each
time
X is doubled the answer becomes the new X. For example, X=10 and Y=3.25.

1.) 10x2=20
2.) 20x2=40
3.) 40x2=80
[Then to get the .25 part]
4.) 80x2=160

160-80=80x.25=20

Answer: 80+20=100.

Any thoughts on a clever way to do this in excel?

Many Thanks!!