What is 21% of 400. I need to know

Asequence {an} is defined recursively, with a1 = 1, a2 = 2 and, for n > 2, an = an-1 an-2 . find the term a241. a) 0 b) 1 c) 2 d) 1 2

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?