Question 567434
A is moving 17 feet per second slower than B.
 How long will it take B to catch A if B starts out 672 feet behind A? 
:
B's relative speed to A is 17 ft/sec, therefore
{{{672/17}}} = 39.53 seconds for B to catch A
:
How far will A have traveled before B catches up?
I don't think you can know this with the information given, all we can say is
A will travel 672 ft less than B travels