Sanghun is paid $100,000 a year for the next 40 years (starting at t = 1 and ending

at t = 40). He also has expenses of $100,000 every other year (starting at t = 1, at

t = 3, 5, 7, . . ., and ending at year t = 39). The annual interest rate is 5%. Calculate

the accumulated value (at t = 40) of the payments minus the expenses