There are 30 different vehicles further split into 15 bikes and 15 karts, and even further split into Small, Medium, and Large categories.
There are 26 characters, counting Mii A and Mii B as separate.
24.
Mario can have 8 karts and 8 bikes.
i think 26
24
Eight starter + Four Unlockbles +One in DS Download Play =13 in all
You could get 24 characters in all
There are eight places in Mario Kart Double Dash. There are always eight karts racing at a time, so every player is ranked 1st through 8th
You can get up to 17 characters in Mario 7 including Mii character. 9 of these are ones that you need to unlock.
32
24, you start off with 12 and unlock 12.
The high score would depend on which Mario Kart you are talking about. Also, in some of the Mario Karts, in Multiplayer mode, you can set how many races you want to do. In the Grand Prix on Mario Kart Wii, your maximam score that you can get in points is 60 points; 15 points per race. In Double Dash!!, you can get a Max Score of 40 points. Most every Mario Kart has a Max Score of 40 points. In Mario Kart Wii, if you set the races to 25, your Max Score (let's say you got 1st every time) would be 375 points. It all depends on how many races and which Mario Kart you are referring to.
Rosalina is not in Super Mario Kart. She is in Mario Kart Wii.