Thread: Probability Teaser Question

What is the average age to which a 90-year old man will live, given that the probability a person age x will die before age x+1 is (x - 89) / 5?

A. 91
B. 91.5
C. 92
D. 92.5
E. 93

Thanks!

Originally Posted by feiyingx

What is the average age to which a 90-year old man will live, given that the probability a person age x will die before age x+1 is (x - 89) / 5?

A. 91
B. 91.5
C. 92
D. 92.5
E. 93

Thanks!

(4/5)x91+(4/5)(3/5)x92+(4/5)(3/5)(2/5)x93+(4/5)(3/5)(2/5)(1/5)x94

92.4896
~92.5