A1: You stop being a loser and do all 3 on one run. sissy

A2: You don't have to do them in one run, but the answer is actually up to you. You have to figure out a combo (as far as where to go on the slope that will allow you to complete all three challenges, because different portions of the slope are better suited to different actions), and then from there, it's all up to you and your skill level with the game. Oh, and some of the challenge sets (1, 2, and 3 star sets for one slope) allow you to get to the third challenge by "bypassing" the first two. For example, on the carving challenges, say the 16 near miss 3-star challenge, if you get up to 16 without stopping, you've automatically completed the other two challenges because they're of a lower number of near misses. Hope this helps, and good luck!