SSC CGL Tier 2 Exam 25 Oct 2015 Paper 1

(3) LCM of 5, 6, 7 and 8 = 840 ∴ LCM = 2 × 5 × 3 × 7 × 4 = 840
∴ Required number = 840x + 3 which is divisible by 9 for a certain least value of x.
Now,
840x + 3 = 93x × 9 + 3x + 3
3x + 3, is divisible by 9 for x = 2
∴ Required number = 840 × 2 + 3
= 1680 + 3 = 1683
∴ Sum of digits = 1 + 6 + 8 + 3 = 18