Calculate the following probabilities. I've been told that X~geom(0.1) means X follows a geometric distribution

(a) For X ~ Geom(0.1), calculate P(X ≤ 10).

(b) For X ~ Geom(0.2), calculate P(5 ≤ X ≤ 10).

(c) For X ~ P(5), calculate P(X < 6).

I know what the geometric formula is for a sequence, does this apply to this though? :S