Harry worked 7 hours last week this is one third as many hours as aiden work how many hours did aiden work

H = number of hours Harry worked
A = number of hours Aiden worked

Harry worked 7 hours last week so we know H = 7
This is one third as many hours as Aiden's time working so H = (1/3)*A
We can multiply both sides by 3 to get 3H = A or A = 3H

If H = 7, then...
A = 3*H
A = 3*7
A = 21

Aiden worked 21 hours

Add up all the sides