Question 1002869
<pre>
                RATE              TIME         CHAIRS

Kimberly        1/45              45             1

Arthur          1/30              30             1

Combined       1/45+1/30           t            6
</pre>
For the combined rate, the expression, best denominator to use should be 90.

{{{2/90+3/90=5/90=highlight_green(1/18)}}} when reduced.


{{{(1/18)t=6}}}

{{{t=18*6}}}

{{{highlight(t=108)}}}