A mining company is considering whether to develop a mining property. It is estimated that an immediate expenditure of $$7,500,000$ will be needed to bring the property into production. Thereafter, the net cash inflow will be $$1,400,000$ at the end of each year for the next $10$ years. An additional expenditure of $$3,200,000$ at the end of $11$ years will have to be made to restore the property to environmental requirements.

a$)(2$ marks$)$ On projects of this type the company would expect to earn at least $9\%$ compounded annually. Advise whether the company should proceed. $($To prove the conclusion, you should show all calculations$).$

b$)(2$ marks$)$ What conclusion should be made if a desire rate is $11\%?$