Answer :
Set a proportion
45/1=315/x
=45x=315
=45/45x=315/45
x=7
It will take 7 hours to travel 315 miles at the rate of 45miles/hour
45/1=315/x
=45x=315
=45/45x=315/45
x=7
It will take 7 hours to travel 315 miles at the rate of 45miles/hour