Independent solution

How to solve this Expected Value question

Setup

Setup

Index the possible payment year by k from 1 through 5. Reaching year k alive requires k-1 survivals.

Pr(T=k)=0.99k1(0.01),k=1,,5\Pr(T=k)=0.99^{k-1}(0.01),\qquad k=1,\ldots,5

Model

Model

The benefit declines by 5,000 for each later payment year.

bk=250005000(k1)b_k=25000-5000(k-1)

Compute

Compute

Sum benefit times probability over the five mutually exclusive death years.

E[B]=k=15[250005000(k1)]0.01(0.99)k1\operatorname{E}[B]=\sum_{k=1}^{5}[25000-5000(k-1)]0.01(0.99)^{k-1}
=740.0747005=740.0747005

Answer

Answer

The expected benefit rounds to 740.

740(B)\boxed{740\quad\text{(B)}}