Conversion:
1 minute=60 seconds
1 hour=60 minutes
The answers:
1)[tex]840 seconds(\frac{1 minute}{60 seconds})=14 minutes[/tex]
2)[tex]960 minutes(\frac{1 hour}{60 minutes})=16 hours[/tex]
3)[tex]19 minutes(\frac{60 seconds}{1 minute})=1,140 seconds[/tex]
4)[tex]5 hours(\frac{60 minutes}{1 hour})=300 minutes[/tex]
5)[tex]1,260 minutes(\frac{1 hour}{60 minutes})=21 hours[/tex]
Hope this helps =)