Answer: Hence, Mr. Itol takes 9 hours, and his assistant takes 18 hours alone.
Explanation:
Let the number of hours Mr. Itol takes be 'x'.
Let the number of hours Mr. Itol's assistant takes be '2x'.
Total number of hours both experts take = 6 hours
According to question, we get that

Number of hours taken by him = x = 9 hours
Number of hours taken by his assistant = 2x =

Hence, Mr. Itol takes 9 hours, and his assistant takes 18 hours alone.