Question 942534
In a 4 x 100 relay race (each leg 100 meters long), the first place runner has a 0.550 second lead and is running at a constant speed of 8.40 m/s. What minimum speed must the second runner have in order to catch up with the first runner by the end of their leg of the race? 
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let x=increase in speed of second runner
8.40+x=catch-up speed of second runner
travel time=distance/speed
..
{{{100/8.40-100/(8.40+x)=0.55}}}
lcd:8.4(x+8.4)
840+100x-840=.55(8.4x+70.56)
100x=4.62x+38.808
95.38x=38.808
x=0.41
8.4+x=8.81
What minimum speed must the second runner have? 8.81 m/s