$28.$ Approximately how much must be saved for retirement in order to withdraw $$100,000$ per

year for the next $25$ years if the balance earns $8\%$ annually, and the first payment occurs one

year from now?

$$1,067,477\mathrm{.}62$

$29.$ You invested $$1,200$ three years ago. During the three years, you earned annual rates of

return of $4\mathrm{.}8\%,9\mathrm{.}2\%,$ and $11\mathrm{.}6\%.$ What is the value of this investment today? $$1,532\mathrm{.}60$

Can you explain how these questions are answered with formulas? thank you :)