Using the appropriate interest table, compute the present values of the following periodic amounts due at the end of the designated periods.

$30,000 receivable at the end of each period for 8 periods compounded at 12%.
$30,000 payments to be made at the end of each period for 16 periods at 9%.
$30,000 payable at the end of the seventh, eighth, ninth, and tenth periods at 12%.

i am confused on when to use which table so an explanation would be great! thank you!