A sole trader has $50 000 to invest and his bank offers an investment opportunity which pays 1% monthly compound interest. The amount of money in the account after / months can be modelled by the following equation. e(t) = loa' a. Find the values of Co and a. b. Find the time taken for the account balance to be doubled. Leave your answer in the exact form. c. The sole trader has another investment option where a different bank offers monthly compound interest. If he invests his $ 50 000 in this account, he could earn $ 1000 interest after 1 month. Find the monthly interest rate paid by this bank. d. Using the above parts determine the best investment option. Justify your