Darryl is an inventor who just designed a new machine. He had to pay $3600 for the parts to construct the machine, and $4500 for the patent he applied for once he built it. If the machine sells for $180, how many machines does Darryl need to sell to break even after the costs?
Darryl paid 3600 + 4500 = $<<3600+4500=8100>>8100 in costs for the parts and patent.
Thus, Darryl needs to sell 8100 / 180 = <<8100/180=45>>45 machines to break even.
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