what is the rate percent when the simple interest on rs . 4000 amount to rs . 320 in 2 years ?
"interest for 1 year = 320 / 2 = 160 interest on rs 4000 p / a = 160 interest rate = 160 / 4000 * 100 = 4 % answer : a"
divide(multiply(const_100, 320), multiply(4000, 2))