For questions 4-6, calculate the simple interest and the amount after the specified period of time.
 4. $328.00 invested at 5% for 3 years.
 4. Interest:
 5. $635.85 invested at 7% for 6 months.
 6. $175.01 invested at 8% for 90 days.
 Amount:
 5. Interest:
 Amount:
 6. Interest:
 Amount: