the compound interest earned on a sum for the second and the third years are $ 1400 and $ 1540 respectively . what is the rate of interest ?
1540 - 1400 = 140 is the rate of interest on $ 1400 for one year . the rate of interest = ( 100 * 140 ) / ( 1400 ) = 10 % the answer is e .
divide(multiply(subtract(1540, 1400), const_100), 1400)