Question 1112619
.
Solve for x
Working together Ben and Frank {{{highlight(cross(was))}}} wash 1,000 dishes in 3 hours. Ben works twice as fast as Frank. 
How long does it take Frank to wash dishes alone?
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Ben alone works as two Francs.


So, you can re-formulate the problem in this way:


<pre>
     Three Francs make a job in 3 hours.
     How long does it take Frank to make this job alone ?
</pre>

As soon as you re-formulated it, the answer is obvious:  It will take 9 hours.