Cash and credit sales, with returned merchandise.

$($a$)$ Merchandise is sold for $$350$ cash.

$($b$)$ $$30$ of merchandise sold for $$350$ is returned for refund.

$($c$)$ Merchandise is sold on account for $$300.$

$($d$)$ $$35$ of merchandise sold for $$300$ is returned for a credit.

$($e$)$ Payment is received for balance owed on merchandise sold on account.