Answer:
<em>6 days</em>
<em></em>
Step-by-step explanation:
Let the time taken by Carpenter working alone =
days
Then time taken by apprentice alone = Twice as that of taken by Carpenter = 2
days
Time taken working together = 2 days
Work done in one day working together = 
Work done in one day by Carpenter working alone = 
Work done in one day by apprentice working alone = 
Work done in one day by Carpenter working alone + Work done in one day by Carpenter working alone =
+
= Work done in one day working together = 

Time taken by Carpenter alone to complete the work = 3 days
Time taken by Apprentice alone to complete the work = 3
2= <em>6 days</em>