Mane Street normally sells 4,000 economy-size bottles of shampoo for $10 per bottle. The cost to manufacture the shampoo is $5 per bottle. Further variable processing costs of $2.1 per bottle for the shampoo would convert it into a shampoo-condtioner, which Mane Street could sell for $16 per bottle. Variable selling costs are $1.3 per bottle for the shampoo, but for the shampoo-conditioner they would be $3.0 per unit. Calculate and enter the amount of minimum selling price per bottle that would provide incentives for Mane Street to process further