How much percentage a given quantity 'a' is of a given quantity 'b' is given as:
(a/b)*100
here you first need to have both your quantities in the same units before you can compute the percentage. You can do so either by converting 5 hours to minutes or by converting 45 min to hours. I will convert 5 hours to min.
1 hour=60 min
Hence, 5 hours= 5*60=300 min
Now both the quantites are in minutes and you can proceed to the calculation of percentage as
%=(45/300)x100 = 15
hence 45 min is 15% of 5 hours!
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