1. You plan a trip on which you want to average 90 km/hr. You cover the first half of the distance at an average speed of only 48 km/hr. What must your average speed be in the second half of the trip to meet your goal? Note that the velocities are based on half the distance, not half the time. Is this reasonable? 2. Not sure. 3. This is the beginning of something new. Our Physics class has started a couple weeks ago, so my fellow classmates & I are still settling into the new concept of our first Physics class; our first time allowed to think "outside the box". I'm very intrigued, but confused. As I said, this is something new in the chapter, & he hasn't given us many details on where to start. I just am confused with which sort of formula to use. I thought back to previous math, & I'm thinking along finding the median. So, I thought about what would work out to divide by 2 to get 90; obviously 180. 48-180=132. So, 132 km/hr would have to be the average speed for the second time...? I know I can't possibly be correct. It's probably something quite obvious that I'm just not catching. So, can someone help me by giving me the proper formula so I can figure it out? I'm just not sure on where to place what... I know conversion formulas, but that is irrelevant right now. Any help would be greatly appreciated.