I can get 2/3 of the formula done, but I'm stumped on the middle section.
Any help is greatly appreciated! I'm trying to calculate a benefit amount
based on earnings, as follows:

66.7% of the first $3,000 of monthly earnings
55% of the next $2,500 of monthly earnings
40% of any balance

The maximum result is $3,500.

Thanks to any and all!