Component failure order probability

Let the random variables $X$ and $Y$ denote the time to failure of component A and component B, respectively, of an instrument. The joint probability density function of $(X,Y)$ is given by $$f(x,y)=\begin{cases}\dfrac{1}{10}e^{-\frac{1}{2}(y+3-x)},&5<x<10, y>x-3,\\0,&\text{otherwise.}\end{cases}$$ The probability, that component B fails before component A, is equal to