Given, three numbers are in the ratio 3 : 4 : 5. Let the numbers be 3a, 4a and 5a. Given, the sum of the largest and the smallest equals the sum of the second and 52. ∴ 5a + 3a = 4a + 52 ⇒ 4a = 52 ⇒ a = 13 Smallest number = 3a ⇒ Smallest number = 3 × 13 = 39