Alexa May, director of accounts, received a bill for $648, dated April 6, with sales terms 2/10, 1/15, n/30. A 3% penalty is charged for payment after 30 days. 6. Find the amount due if the bill is paid on or before April 16. 7. What amount is due if the bill is paid on or between April 17 and April 21? 8. What amount is due if Alexa pays on or between April 22 and May 6? 9. If Alexa pays on or after May 7, how much must she pay?