Question 778983
Robert bikes at 14 Km/h for 15 min (1/4 hour) before Lionel starts, so 1/4 of 14 is 3.5 Km.  Also Lionel spots Robert 500m which is .5 Km we then have
17t = 14t +3.5 +.5
3t = 4
t = 1 1/3 hours
t = 1 hour and 20 minutes