5-16. Suppose a bivariate random variable (X,Y) has a probability density function of the form f (x, y) = -θ2e−θ(x+y), θ > 0, x ≥ 0, y ≥ 0;

0 elsewhere.

Find P(0 ≤ X ≤ 100, 0 ≤ Y ≤ 100).