find the c . i . on a sum of rs . 1800 for 6 months at 20 % per annum , interest being compounded quarterly ?
"c . i . = 1800 ( 21 / 20 ) ^ 2 - 1800 = 792 answer : c"
subtract(multiply(1800, multiply(add(const_1, divide(const_0_25, const_4)), add(const_1, divide(const_0_25, const_4)))), 1800)