Final answer:
Harry worked 1/3 as many hours as Aiden. Multiplying Harry's 7 hours by 3 gives us Aiden's total hours of 21. Option b (21 hours) is the correct answer.
Step-by-step explanation:
The student is asking a proportional relationship question, where we are given that Harry worked 7 hours and that this is 1/3 as many hours as Aiden worked. To find out how many hours Aiden worked, we need to calculate the full amount of which 7 hours is 1/3.
To do this, we set up the equation: 7 hours = 1/3 of Aiden's hours. To find Aiden's total hours, we multiply 7 by 3, which equals 21 hours.
Therefore, the main answer is that Aiden worked 21 hours last week, which corresponds to option b. 21 hours.