I am unable to understand the 3rd part of the question my method-1. thief covered 80km from 6am to 8 am at 40kmph and then halted at a shop for 15 mins.2. police starting chasing him at 8am @ 60kmph and in 15 mins covered 15 kms.3. so now the distance between chor police should be (80-15=65 km).4. chorr again starts running and police is also chasing him at 20kmph relative speed.5. so time at which police will catch thief = (65/20=3.25 hrs).i.e 8:15am + 3hrs and 15 min = 11:30am.what I am unable to understand is 1.how that 70/20 came in the video solution?2. from 6am to 8am thief covered 80km and then took break for 15 min till 8:15am. If in case he hadn't took any break then in those 15 mins he would have traveled 10 kms and the distance between police and chor would be 90 kms(6am to 8:15am). But police also started chasing him from 8am so the distance was actually 75kms.3. my point is even if he didn't  took break for 15 min at 8am then also the distance between police and chor would be 75km and not 70km.I am not able to understand where I am going wrong.