Stats doubt

Posted by Shefali on Jun 11, 2014; 8:23am
URL: http://discussion-forum.276.s1.nabble.com/Stats-doubt-tp7592360.html

Suppose that X and Y have a continuous joint distribution
for which the joint p.d.f. is defined as follows:
f (x, y) =cy^2 for 0 ≤ x ≤ 2 and 0 ≤ y ≤ 1,
                       0 otherwise.
Determine (a) the value of the constant c;
 (b) Pr(X +Y >2);
(c) Pr(Y < 1/2);

how to do part b and c...hw do we set limits for such quest?pls help..