
Peter M. answered 05/12/20
Experienced math tutor
arithmetic sequence: after n years, with A he has earned 40n + n(n-1)
geometric sequence: after n years, with B he has earned 36 (1-1.06^n)/(1-1.06)
Using my graphing calculator, it will take 13 years before offer B will exceed offer A. So he should accept offer A.