An elderly patient is a candidate for an experimental operation. The operation has a 70% chance of allowing her to live 8 more years on average; a 20% chance of having no effect and allowing her to live 4 more years on average; and a 10% chance of making the condition worse
and allowing her to live 1 more year on average. What is the expected number of years the patient will live if she undergoes the operation?
Select the best answer from the choices provided.
A 2.2 years
B. 2.3 years
C. 6.4 years
D. 6.5 years