Answer:
It would take the clerical worker 6 hr to finish the job working alone.
Step-by-step explanation:
Let x be the time taken( in hours ) by executive to finish the job when he works alone,
⇒ One hour work of the executive = 
According to the question,
Time taken by clerical worker to finish the job alone = 2x hours,
⇒ One hour work of the clerical worker = 
Total work in one hour when they work together = 
Now, it takes them 2 hr to finish the job together,
So, total work in one hour when they work together = 




Hence, time taken by clerical worker to finish the job alone = 2(3) = 6 hours