(1 point) (Exercise 2.16) It is known that an investment of $2000 will accumulate to $3300 at the end of 9 years. If it is assumed that the investment earns simple interest at rate i during the 1st year, 2i during the 2nd year,..., 9i during the 9th year. find i. n(n+1) (Hint: 1 +2 + ... +n=- i =