Let the number be x and y. Then, according to the question, x + y = 15 ...(i) x - y = 3 ...(ii) On adding Eqs. (i) and (ii), we get 2x =18 = x = 9 On putting the value of x in Eq. (i), we get y = 6 Therefore, Product = xy = 9 x 6 = 54