This is the same question, asked twice !
-- The first time, multiply each side by ' t ' and you get one of the choices.
-- The second time, you have a choice of two ways.
==> Way #1: Multiply each side by ' t ', then divide each side by ' r ', and you have one of the choices.
==> Way #2: Take your answer from #67, divide each side by ' r ', and you have the same one of the choices.
