Loaded-Up Fund charges a 12b-1 fee of 0.75% and maintains an expense ratio of 0.50%. Economy Fund charges a front-end load of 3.0%, but has no 12b-1 fee and an expense ratio of 0.25%. Assume the rate of return on both funds portfolios (before any fees) is 8% per year.

How much will an investment of $1,000 in each fund grow to after 1, 3 &10 years?

I understand the formula for the "Load Up" Fund (at least I believe I do.. I could really use some help understanding not only the formula used for the Economy Fund but also the logic behind it.

Load up
=Investment*(1+(Rate of Return - 12b-1 - expense ratio)^n

Thank you!