Answer and explanation:
Profit from sale of model boats = Sales -costs(costs of goods purchases + expenses or charges by the local fair)
John's profit from the sale of model boats can be represented by the equation:
P= 50x-(5x+80)
Where P is profit from the sale of the model boats and x is number of model boats bought and sold. The 80 is constant as it is a fixed cost paid to the local fair.
For example if John buys and sells 20 model boats, he would make profit of:
Substitute x=20 in equation above
P= 50×20-(5×20+80)
P=1000-180
P=$820
It could be said that John is in a very profitable business and his profit is also dependent on volume of sales because the lower his sales the closer he gets to making a loss and not profit