Lee is a computer programmer who earned $$35,000$ in $2016.$ But on January $1,2017,$ Lee opened a body board manufacturing business. At the end of the first year of operation, he submitted the following information to his accountant:

$$ He stopped renting out his cottage for $$3,500$ a year and used it as his factory.

$$ He spent $$50,000$ on materials, phone, etc.

$$ He leased machines for $$10,000$ a year.

$$ He paid $$15,000$ in wages.

$$ He used $$10,000$ from his savings account, which earns $5$ percent a year interest.

$$ He borrowed $$40,000$ at $10$ percent a year.

$$

a$.$ Why do accountants and economists calculate a firm$$s cost and profit in different ways? $$ Explain $(50-60$words$).$

b$.$ Calculate Lee$$s economic profit. Show all calculations