Let us assume that the time taken by the category 3 hurricane to travel from Cuba to Key West = X minutes
Speed of the category 3 hurricane is given as 20.88 km/hr
So the category 3 hurricane can travel 20.88 km in 1 hour.
The distance between Cuba and Key West = 145 km
Then
20.88 km is travelled by the category 3 hurricane in = 60 minutes
145 km from Cuba to Key west is travelled by the category 3 hurricane in = X minutes
So,
X = [(145 * 60)/20.88] minutes
= 416.66 minutes
= 17 hours and 36 minutes
Time taken by the category 3 hurricane to reach Key West from Cuba is 17 hours and 36 minutes.