Probability and Statistics

[Sinistral]

2) Let X1, X2 and X3 be iid with the common pdf f(x) = exp(-x) 0 < x < infinity, zero elsewhere.
Evaluate:

P(X1 < X2 | X1 < 2X2)
and
P(X1 < X2 < X3 | X3 < 1).