Question 266383
(1.00-.04)(1+r -.0050^6=1.4185 
       .96(1+r -.005)^6=1.4185
          (1+r -.005)^6=1.4776
r+.995
r+.995
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r^2+.995r+.995r+.990025
r^2+1.99r+.990025
r+.995
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r^3+1.99r^2+.990025r+.995r^2+1.97r+.985
r^3+2.985r^2+2.96r+.985
r+.995
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[I don't really think you want to go down this road, it's more work than I believe you can handle.
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The following is the straight forward solution using roots.
(r+.995)=6throot(1.4776)
r+.995=1.06723
r=1.06723-.995
r=.0722 ans.