$1)$What amount should be deposited at the end of each quarter in a sinking fund earning $8$ percent compounded quarterly if the amount in the fund after $4$ years is to be $$90,000?2.$ A company offers its salespeople a bonus of $$500$ per quarter for $3$ years. To win a bonus, a salesperson must have sold at least $$1$ million worth of the company$$s products in the period January $1$ through December $31,$ and the first bonus payment is made at the end of the first quarter following. The company funds each bonus on December $31$ by a lump$-$sum deposit in a bank account that pays $8$ percent compounded quarterly, and the bank sends out the bonus checks; a$)$ What total sum is received by each bonus winner? b$)$ How much does it cost the company to fund each bonus?