Delivering an agreement

— I'll fax a copy of the agreement to you right away.
— Our fax machine's been kind of spotty lately. Would it be possible to send it as an e-mail attachment? I'll print it out, sign it, and then mail it back.
— That would work, except that we need it by noon tomorrow. Will it get here in time if you send it snail mail?
— It will if I send it overnight delivery. They guarantee a noon arrival.