If the USD/GBP exchange rate was 1:6595; the 60 day forward rate was 1:6545; and the 2-month U.S. Treasury bill rate was 4:58%:What is the 2-month yield of British T-bills if covered interest parity holds: (a) 6.39; (b) 4.55; (c) 3.33; (d) 4.58;

I have the formula, how do i get 'e' and 'f' for the formula [1 + i(T/360)] * e/f = [1 + i_f(T/360)]