Question 171033
LET 60*T= THE WEST CAR.
LET 80(T-1.5)= THE EAST CAR.  
60T+80(T-1.5)=620
60T+80T-120=620
140T=620+120
140T=740
T=740/140
T=5.2857 HOURS AFTER THE CAR GOING WEST STARTED THEY WILL BE 620 MILES APART
PROOF:
60*5.2857+80(5.2857-1.5)=620
317.14285+80*3.7857=620
317.14285+302.856=620
620~620