John and David are running the 1-mile race. David enters the final quarter first and is running at a rate of 18 ft./sec. John enters the final quarter 3 seconds later but is running at a rate of 20ft./sec. Who will win the race? hint 5280ft.= 1mi.

Question

anonymous · Answer

Well, a quarter of a mile is or can be given by (1/4)(5280), or 1320 feet

anonymous · Answer

We use a little formula here: D=R*T, which basically stand fro Distance =Rate*Time

anonymous · Answer

have you tried this problem on your own? what was your answer?

anonymous · Answer

yeah but i dont get it

radar · Answer

You understand who gets to the finish line first is the winner.

Since David enters the final quarter mile (1320 ft) 3 seconds before John, he has a head start and has traveled 3 times his blistering speed of 18 ft. per second, or 54 feet, and has only 1320-54 feet or 1266 feet left when John enters the last quarter mi.

Now the question is who gets there first?  Will David cover his remaining 1266 feet at 18 ft/sec before John travels his 1320 ft at his rate of 20 ft/sec.

You now have the data needed to solve. D=R*T    Rearrange to solve for time getting
T=D/R.  Plug in the D and R values for David  and then John and see which T is the lesser, that will be the winner.

David T will be 1266/18
John T will be 1320/20

The moral of this story is he who gets to the last qtr first may not be the one who finishes first.