A refrigerator is produced at a cost of $200 to the manufacturer. On this cost is added a margin of 20 percent (based upon cost) and the refrigerator is shipped to an independent wholesaler. The wholesaler then adds a 50 percent margin based upon its selling price. This figure represents the cost to the retailer. If the retailer then charged the consumer $960, what margin had the retailer employed on their cost? please show work.

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