Consider a mutual fund with a $4\%$ front load and with $$500$ million in assets at the start of the year, and $12$ million shares outstanding. If the gross return on assets is $12\%$ and the total expense ratio is $0\mathrm{.}9\%$ which will be charged at the end of the year based on the end of year value, The estimated rate of return on the fund for the first year is $\_\_?($two decimal places, for example, $3\mathrm{.}41$ not $0\mathrm{.}034)$ the answer is $6\mathrm{.}55$ teach me how to work it out.