Imagine you have a profit of 100 now. But instead of being able to spend that profit, you have to place it in reserve for one year (ie you are holding a reserve of 100 for one year). What is the EPV of the profit now?
It will be 100x(1+i)/(1+r), where i=interest rate earned on reserves, and r=risk discount rate.
So, when i=r, the EPV of the profit stays the same (=100). But in the more normal case where i<r, the EPV is less than 100.
But in this question, i=r, so the holding of any amount of reserves will make no difference to the EPV of the total profit.
Robert