RoadSignMath.com (RSM) was a near instant success and consequently the RSM Administrator (RSMadmin) is suffering from the "sign, sign, everywhere a sign" syndrome. The following was posted to RoadSignMath.com on 23 January 2007.

"Hello faithful fans of Road Sign Math! I'm here to give you all
an update on the future of our wonderful driving game.  Anyone
that frequents the website will notice that sign postings have
dried up almost completely. This isn't for lack of signs being
found, I have about 50 of them in my incoming mailbox.  It is
however just a pure lack of time to do the work. It takes 10-15
minutes as it stands to post a single sign on Road Sign Math.
You can do the math...  15 x 50 = 750 minutes = 12.5 hours"

[...]

"Remember:  driving + math = fun"
Exercises
1. The RSMadmin said, "You can do the math... 15 x 50 = 750 minutes = 12.5 hours." Rewrite the 15 x 50 expression using units.

2. Explain why 750 minutes = 12.5 hours.

3. The RSMadmin said it takes between 10 minutes and 15 minutes to post a sign to RoadSignMath.com; therefore, the average length of time to post a sign is __________ minutes.