the difference between the compound interest and simple interest on a certain sum at 10 % per annum for 2 years is $ 631 . find the sum ?
let the sum be $ x c . i . = x ( 1 + 10 / 100 ) ^ 2 - x = 21 x / 100 s . i . = ( x * 10 * 2 ) / 100 = x / 5 c . i . - s . i . = ( 21 x / 100 ) - ( x / 5 ) = x / 100 x / 100 = 631 x = 63100 answer is d
divide(multiply(multiply(const_100, const_100), 631), const_100)