Question $3(1$ point$)$

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Suppose you receive a $$20,000$ advance today for your promising project from an investor. Additionally, you expect to receive a $$90,000$ payment three years from now. However, for the maintenance of your project, you must pay $$10,000$ immediately, $$50,000$ at the end of the second year, and $$30,000$ at the end of the third year. Assuming a Minimum Attractive Rate of Return $($MARR$)$ of $10\%,$ determine the approximate external rate of return $($ERR$)$ for this project. The ERR should be expressed as a decimal rate $($for example, $0\mathrm{.}01$ for $1\mathrm{.}00\%).$