1. The problem statement, all variables and given/known data John is entering Steward, and drives West, with a Uav of 88 km/h. He arrives at Aurora, and realises he took a wrong turn. He turns around and drives East, towards York, with a Uav' of 79 km/h. Steward-Aurora is 76 km & and Aurora-York is 34 km. For the whole trip (S -> A -> Y) find: a) What's the average metre (meaning the positive value of a quantity, eg | -70| = 70) of his speeds (U)? b) What's the metre of his average speed? 2. Relevant equations Uav = (Xfinal - Xstarting)/(tfinal - tfirst) X=U*t 3. The attempt at a solution S->A: Ssa = |Usa|*tsa <=> 76 km = 88 km/h*tsa <=> tsa = 0,86h A->Y: Say = |Uay|*tay <=> 34 km = 79 km/h*tay <=> tay = 0,43 h Sc = (76 + 34) km = 110 km tc = (0,86 + 0,43) = 1,29 h Okay, so, the answers are: a) 85 km/h b) 32 km/h Personally, I think he got them mixed up. The metre of his average speed (b) if I'm not mistaken, should be: |Uav| = Sc/tc = 110 km/ 1,29 h ~ 85 km/h So, it's just a typo, right? Well, thing is, for the life of me, I can't understand what question (a) means. I translated it here as well as I could. So, any ideas? Any kind of help would be appreciated!