How many skeletons do I need to kill to get level 30 in Minecraft?
Skeletons give 5 experience (and 1 to 3 depending on which weapon they spawned with)(Source). You need a total of 1395 experience for level 30 (Source). Assuming you get on average 7 experience, then in total you need to kill 1395 / 7 = 199 Skeletons.