if the simple interest on $ 1500 increase by $ 20 , when the time increase by 2 years . find the rate percent per annum .
applying the above formula , we have 20 = 1500 * r * 2 / 100 r = 20 * 100 / 1500 * 2 = 0.7 % . answer is e
multiply(divide(divide(20, 2), 1500), const_100)