(b) Distance between two cars leaving from the station A is, d = 61 x 60 = 10 km Man meets the first car after time, t1=60+6060=21 h He will meet the next car after time,t2=60+6010=121 h In the remaining half an hour, the number of cars he will meet again is, n = 12121 = 6∴ Total number of cars would be meet on route will be 7.