Crystal Report - Lost time for scrap

I am trying to create a report for management that shows us the time lost on scrap pieces. The formula for the lost time on the current operation is ScrapQty/ProdStd. What I need to figure out is the same type of formula but for the lost time on the current scrap pieces / previous operation sequences Prod std.
We had 10 pieces scrap on Op 30. Op 30 Prod Std = 40pph. Lost time is .25 hours.
Now I want the lost time for these same 10 pieces in relation to the previous 2 operations.
Op 10 Prod std = 50 Lost time for these 10 pieces on Op 30 = .20 hours
Op20 Prod std = 20 Lost time for these 10 pieces on Op 30 = .50 hours

Total lost time for these 10 pieces of scrap = .95 hours.

Any one have any idea on how to have the current operation scrap pieces divide into the Prod std for previous operations?

Thanks for your help.



Melissa Hietala
UMC, Inc.
melissah@...

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