=IRR(values,[guess])

Microsoft Excel uses an iterative technique for calculating IRR.
Starting with the [guess], IRR cycles through the calculation until the
result is accurate within 0.00001 percent. If IRR can't find a result
that works after 20 tries, the #NUM! error value is returned.

In most cases you do not need to provide guess for the IRR calculation.
If guess is omitted, it is assumed to be 0.1 (10 percent).


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Lotus123
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