239 dirhams: five are due on the first 200, with no extra due for the incomplete 39-dirham increment under this view. Total: 5 dirhams.
240 dirhams: five on 200 plus one on the completed extra 40. Total: 6 dirhams.
The difference concerns how increments above nisab are treated, not the basic rate itself.
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Zakat on Silver: Nisab, Incremental Dues and Alloyed Dirhams
239 dirhams: five are due on the first 200, with no extra due for the incomplete 39-dirham increment under this view. Total: 5 dirhams.
240 dirhams: five on 200 plus one on the completed extra 40. Total: 6 dirhams.
The difference concerns how increments above nisab are treated, not the basic rate itself.