Answer:
15 seconds x (1 hour/3600 seconds)
Step-by-step explanation:
By the factor label method. There are 60 seconds in a minute and 60 minutes in an hour.
15 seconds x (1 minute/60 seconds) x (1 hour/60 minutes) = your answer
Soon enough you'll realize that 60x60=3600 and so there are 3600 seconds in 1 hour. Then you will only need 1 conversion ratio;
15 seconds x (1 hour/3600 seconds) = your answer