Let X1,X2∼Exponential(λ=1)X_1, X_2 \sim \text{Exponential}(\lambda=1)X1,X2∼Exponential(λ=1). What is the probability P(X1+X2<1)P(X_1 + X_2 < 1)P(X1+X2<1)?
1−e−11 - e^{-1}1−e−1
1−2e−11 - 2e^{-1}1−2e−1
1−e−1(1+1)1 - e^{-1}(1+1)1−e−1(1+1)
0.50.50.5