Could someone explain this problem to me with equation and how input it in a financial calculator:

1. You buy a T-bill that will pay you $10,000.00 in 177 days. You pay $9998.033 for it.
2. A student reported to the class that she deposited $500 in a brokerage account. The account is now worth $3,000. She was a little uncertain of when she opened the account and believes it was in the last 3 to 5 years.