find the compound interest on $ 15,624 for 9 months at 16 % per annum compounded quarterly .
"p = $ 15625 , n = 9 months = 3 quarters , r = 16 % p . a = 4 % per quarter . amount = $ [ 15625 * ( 1 + ( 4 / 100 ) ^ 3 ) ] = $ ( 15625 * ( 26 / 25 ) * ( 26 / 25 ) * ( 26 / 25 ) ) = $ 17576 . c . i = $ ( 17576 - 15625 ) = $ 1951 . answer ( b )"
subtract(multiply(15,624, power(add(const_1, divide(16, const_100)), 9)), 15,624)