Do you understand the solution? I think some conditions are provided just in the solution itself, for example, Liquidity: $6 million, is it a condition given in the problem or just given in the solution itself?
The $6mln is a rough number. Because the fund has a 10 year time horizon and will eventually have $60mln in capital (plus any additional returns) the fund must payout enough to have a zero capital base in 10 years time. Therefore, paying out approxiamtely $6mln per year (depending on returns it could be more or less) would be necessesary in order to deplete the fund by year 10. This means each year the liquidity requirements of the fund are approximately $6mln.