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Ten deposits of 100 are made into a fund at two-year intervals with the first deposit at the beginning of the first year. The fund earns interest at an annual effective rate of 1.8% during the first eight years and at an annual effective rate of 3.8% thereafter. Calculate the annual effective yield rate earned over the investment period ending at the end of the 20th year. 3.1% 3.2% 3.3% 3.4% 3.5%