The applicable relation is
... selling price = cost + markup
You have not said what the base is for the markup percentage. If markup is 75% of the cost, then we have
... markup = 0.75×cost
... cost = markup/0.75 = 3237.50/0.75 = 4316.67
Then the selling price is
... selling price = $4316.67 +$3237.50 = $7,554.17
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If the markup is 75% of the selling price, then we have
... markup = 0.75×selling price
... selling price = markup/0.75 = $3237.50/0.75 = $4,316.67
