Answer:
1 min : 12 min
Explanation:
To simplify the given ratio, convert both to the same unit of time.
1 hour = 60 minutes
3 hours = 3 x 60 minutes
= 180 minutes
So that,
15 min : 3 hours = 15 min : 180 min
divide through by 15 to have;
15 min : 180 min = 1 min : 12 min
Thus the simplified form of the number give is 1 min : 12 min.