So let's say I have two **independent** random variables $X \sim U(0,1)$ and $Y \sim U(0,1)$. I want to find the probability $P(Y>2X)$

For a uniformly distributed random variable $P(X<a) = F(x) = \frac{x-a}{b-a}$

However, I'm not sure how to calculate the probability when $a$ is a random variable.