the present worth of $ 3600 due in 2 years at 20 % per annum compound interest is ?
present worth = 3600 / ( 1 + 20 / 100 ) ^ 2 = 3600 * 5 / 6 * 5 / 6 = $ 2500 answer is e
divide(3600, power(add(divide(20, const_100), const_1), 2))