Tom decides to invest $500000 and is considering two offers from two different banks. Offer 1 provides 3.7% compound interest compounding annually; Offer 2 allows Tom to invest $100000 each year and receive no yield on the first 5 years, then receive a different yield each year starting year 6 (Table 1). Which offer should Tom choose if the investment period is 10 years? 15years? 20 years?

\begin{tabular}{|r|r|} \hline \multicolumn{2}{|c|}{ Bank 2 } \\ \hline Year & Rate of Return \\ \hline 1 & 0 \\ \hline 2 & 0 \\ \hline 3 & 0 \\ \hline 4 & 0 \\ \hline 5 & 0 \\ \hline 6 & 12.91% \\ \hline 7 & 3.93% \\ \hline 8 & 4.11% \\ \hline 9 & 4.25% \\ \hline 10 & 4.40% \\ \hline 11 & 4.56% \\ \hline 12 & 4.72% \\ \hline 13 & 4.88% \\ \hline 14 & 5.05% \\ \hline 15 & 5.23% \\ \hline 16 & 5.41% \\ \hline 17 & 5.60% \\ \hline 18 & 5.80% \\ \hline 19 & 6.00% \\ \hline 20 & 6.21% \\ \hline \end{tabular}