Assuming biannual compounding, how long will it take Prakash's account to go from $3,988 to $5,012 if the interest rate was 4.77%? If compounding is yearly, what was the interest rate if Maggie's account doubled over the course of 7 years? How much was deposited into Larry's account if, after 4 years, 3 months, it currently sits at $10,990 from a 6.22% interest rate, assuming monthly compounding? Suppose there is $4,500 in a person's account after 3 years. Assuming simple interest, how much was deposited into the account if the interest rate was 2.1%?