Answer
$86,400~messages$
Work Step by Step
$1~week=7~days$, $1~day=24~h$, $1~h=3600~s$ and $7~s=1~message$
$1~week=(1~week)(\frac{7~days}{1~week})(\frac{24~h}{1~day})(\frac{3600~s}{1~h})(\frac{1~message}{7~s})=$
$86,400~messages$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.