Lenny D. answered 01/05/20
Former professor at Tufts University with decades on Wall Street
Let S= speed of Slow cyclist.l The fast cyclist , F travels at S+6. The rate of closure between the two is Rate=(2S+6) Distance is Velocitiy*Time. Distance is 180 and time is 5 hours.
soooo, 5*(2S+6)= 180 Expanding we get 10S+30 = 180 or 10S=150 or S=15. The slow rider pedals at 15 MPH and The faster at 21 mph. To check our work we see the low rider covers 15MPH*5hours = 75 miles. The other rider covers 21*5 = 105 miles. Between the two of them they cover the whole 180 miles.
Lenny D.Sorry, I answered a different question here. D= 90, T=2 F= S+5 Rate of convergence = F+S = 2S+5. Rate of Conergence *T = 90 or (2S+5)*2=90 or 2S=5 =45 or2S=40 or S= 20 and F=25 in 2 hours S travels 40 miles and F travels 50 for a total or 90