[AccessD] Maths Simplification

It can also be written as  x * (y ^ 0  +.... y ^ 1 ... y  ^  z)

It is called  a Geometric series. The general solution  is:

s =  x * (1-y^z)/(1-y) 

So: x = 100, y = 0.2 and z = 3

100 * (1 - 0.2 ^ 3) / (1 - 0.2)  =   124

-- 
Stuart


On 2 Nov 2013 at 19:31, David Emerson wrote:

> Not strictly Access but here goes.
> 
> 
> 
> I have a number (X) that measures the number of text messages to be
> sent in a batch.
> 
> In a batch Y messages will fail to send.
> 
> Any failed messages will be sent as a fresh batch which will also have
> Y messages that will fail to send.
> 
> The number of times a set of messages should be resent is Z
> 
> 
> 
> The formula to calculate how many messages are sent including resends
> is:
> 
> 
> 
> X + (X*Y^1) + (X*Y^2) .. + (X*Y^Z)
> 
> 
> 
> For example, 100 messages with a 20% fail rate to be sent 3 times is:
> 
> 
> 
> 100 + (100 * .2) + (100 * .2^2) = 100 + 20 + 4 = 124
> 
> 
> 
> I could write this as a loop for Z times and add the values but I was
> wondering if there was a single line formula which does the same
> thing?
> 
> 
> 
> Just curious.
> 
> 
> 
> Regards
> 
> David Emerson
> Dalyn Software Ltd
> Wellington, New Zealand
> 
> 
> 
> 
> 
> 
> 
> -- 
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