Required: A pension plan is obligated to make disbursements of $$2\mathrm{.}1$ million$$3,1$ million, and $$2\mathrm{.}1$ million at the end of each of the next three years, respectivelyFind the duration of the plan's obligations the interest rate is $12\%$ annually. $($Do not round intermediate calculationsRound your answer to $4$ decimal places.$)$