You just turned $25$ years old and want to retire when you turn $65.$ You expect to withdraw $$100,000$ per year for $25$ years during retirement, starting first withdrawal one year after your $65$ th birthday.

You expect to earn a return of $4\%$ on your investments every year.

How much retirement saving do you need to have by $65$ th birthday to support the withdrawals in the next $25$ years? Or the same question can be asked differently, what is the present value $($as of your $65$ th birthday$)$ of the withdrawals you expect to make