simplify the ratio. Use values in terms of the smaller measurements units.

9 1/4 days to 3 weeks. This is the same as:

9 1/4 days to 21 days. Now we can turn this into "hours" by multiplying both sides by 24:

222 : 504 hours. If you want smaller units(minutes in this case), just multiply both sides by 60 and so on.

9 1/4 days = 9.25 days

3 weeks = 21 days

So

9.25 days  :  21 days =

37  :  84      [in terms of an integer ratio ]