$333,062,500. To begin with, you want to know the total number of days: 365 x 50 = 18250. By experimentation, the following formula can be discovered, & used to determine the amount earned for any particular day: 1 + 2(x-1), with x being the number of the day. The title again holds a hint, although this 1 may have been a bit more obscure. Take half of the 18250 days, & pair them up with the other half in the following way: day 1 with day 18250, day 2 with day 18249, & so on, & you will see that if you add these pairs together, they always equal $36500. Multiply this number by the total number of pairs (9125), & you have the amount you would have earned in 50 years. Except for math gurus (I'm not 1), this puzzle may have proved to be tough. Someone pointed out that a much easier method for solving this problem is squaring the total number of days worked - I like doing things the hard way, though.