$($Round all answers to the nearest cent.$)$

$($a$)7\mathrm{.}5\%$

payment $ $$

total interest $ $$

$($b$)7\mathrm{.}75\%$

payment $

total interest $ $$

$($c$)8\mathrm{.}0\%$

payment $ $$

$($d$)9\mathrm{.}0\%$

payment

$ $$ total interest $