Question 495388
<pre>
That's exactly right.  You just need to finish

640x + 560x = 2100
      1200x = 2100
          x = {{{2100/1200}}}
          x = {{{7/4}}}
          x = {{{1&3/4}}}

That's 1 hour and 45 minutes.
   
I hour and 45 minutes from 10:30 am is 12:15 pm.

Edwin</pre>