Answer:
$0.16 per floss unit
Step-by-step explanation:
You want the cost per floss unit for 25000 units if the cost varies inversely with units produced and 8000 units are produced for $0.50 per unit.
The number of units is increased by a factor of 25000/8000, or 25/8. If the cost is inversely proportional, it will be reduced by the factor 8/25:
($0.50/unit) × 8/25 = $0.16/unit
The cost is $0.16 per floss unit if 25,000 units are produced.
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Additional comment
The inverse variation means ...
(cost/unit) × units = constant
That is, the cost of floss unit production is $4000, regardless of the number of units produced.