2004 #12 and 30

I find it probable that even sum of your odd students will get this one.

Difficulty: Easy.

Difficulty: This one took a minute to even get started.

Standard instructions for this series: No calculator allowed. Express answers in reduced form. Rationalize denominators. Radicals must be reduced. All numbers are base ten unless otherwise specified. Do not approximate radicals or π. Leave such answers as 1025π or √39, for example. Source: UVM Math Contest 2004

answer 12, answer 30.