need help with set-up

[megs915]

Give the joint density f(x,y)= 60xy^2 if 0<x<y<1 and 0 otherwise, find P(X+Y<1). I just need help setting up the integral...I don't know what to integrate from. Please help!

[quark]

A plot would be helpful here. The domain 0<x<y<1 is a triangle, and the area over which you want to integrate is the area in the triangle satisfying x+y<1.