find the compound interest on $ 500 in 5 years at 5 % per annum , the interest being compounded yearly ?
"principle = $ 500 rate = 5 % yearly amount = 500 * ( 1 + 5 / 100 ) ^ 5 = 500 * 21 / 20 * 21 / 20 * 21 / 20 * 21 / 20 * 21 / 20 = $ 638.14 c . i . = 638.14 - 500 = $ 138.14 answer is a"
subtract(multiply(500, power(add(const_1, divide(5, const_100)), 5)), 500)