Independent solution

How to solve this Expected Value question

Setup

Setup

A high-risk driver has expected annual bonus 12×5×0.80=48, while a low-risk driver has expected annual bonus 54.

E[BH]=12(5)(0.80)=48E[B_H]=12(5)(0.80)=48
E[BL]=12(5)(0.90)=54E[B_L]=12(5)(0.90)=54

Model

Model

Weight the two annual expectations by their cohort sizes, 600 and 400, and add them.

E[T]=600E[BH]+400E[BL]E[T]=600E[B_H]+400E[B_L]

Compute

Compute

The high-risk cohort contributes 28,800 and the low-risk cohort contributes 21,600, totaling 50,400.

E[T]=600(48)+400(54)=28800+21600=50400E[T]=600(48)+400(54)=28800+21600=50400

Answer

Answer

Expected total annual bonus is 50,400, corresponding to choice B.

50,400(B)\boxed{50{,}400\quad\text{(B)}}