· Author has 184 answers and 67.6K answer views Let the number be (10 x + y) Then, 10 x + y = 3 * (x + y) (given) Or, 10 x + y = 3 x + 3 y Or, 10 x - 3 x = 3 y - y Or, 7x = 2 y Or, x = 2 y / 7 ( Eq. 1) Also, 10 x + y + 45 = 10 y + x ( given) Or, 10 x - x = 10 y - y - 45 Or, 9 x = 9 y - 45 ( Eq. 2) Substituting the value of x from (Eq. 1) in (Eq. 2), we have: 9 * 2 y / 7 = 9 y - 45 Or, (9 y ) - (18 y / 7) = 45 Or, 63 y - 18 y = 315 Or, 45 y = 315 Or, y = 7 From (Eq. 1), x = 2 * 7 / 7 = 2 So, the number is 10 x + y = (10 * 2) + 7 = (20 + 7) = 27 Answer Check: Sum of the digits = 2 + 7 = 9 9 * 3 = 27 ✓ Adding 45 to the number 27, we get 72. So, the digits get reversed.