Lavage Rapide owns and operates a large automatic car wash facility near Montreal. The following table provides estimates

concerning the company's costs:

For example, electricity costs should be $$1,400$ per month plus $$0\mathrm{.}10$ per car washed. The company expects to wash $8,100$ cars in

August and to collect an average of $$6\mathrm{.}20$ per car washed.

The actual operating results for August are as follows:

Required: