This is what I typed =LOG(50,100)/LOG(0.8)
and I get -8.76571

"David Biddulph" wrote:

So what numbers did you plug in to the formula to get -12 something?

If EndVal is half of BeginVal (which is what you asked for), the answer is
3.106284
--
David Biddulph

"Rick" wrote in message
...
I tried the log function below but it did not work...it gave me -12
something.

"Barb Reinhardt" wrote:

Or something like this

# iterations =LOG(EndVal/BeginVal)/LOG(0.8)

"Gary''s Student" wrote:

In A1 put 100 and
In A2 thru A10 enter:

=A1*0.8
=A2*0.8
=A3*0.8
=A4*0.8
=A5*0.8
=A6*0.8
=A7*0.8
=A8*0.8
=A9*0.8
to see:

100
80
64
51.2
40.96
32.768
26.2144
20.97152
16.777216
13.4217728

and as you can see 4 iterations got use below 50.
--
Gary''s Student - gsnu200720


"Rick" wrote:

Sorry I forgot to write that if you start out at 100 how many
iterations does
it take to go below 50...using the residual value

"Gary''s Student" wrote:

If a value starts with a non-zero amount, then it can NEVER reach
zero if it
decrease by 20% of its residual value.

If you decrease it 20 % of its original value it will take 5
Iterations:

100
80
60
40
20
0

--
Gary''s Student - gsnu200720