Let Three digit No is 100 a + 10 b + c Given 100 a + 10 b + c = 100 a + 10 c + b – 36 9b – 9c + 36 = 0 c = b + 4 b = c – 4 ...(i) Also given 100 a + 10 b + c = 100c + 10 b + a + 198 99 a – 99 c = 198 a = c + 2 ...(ii) ∴ Now 100 a + 10 b + c – (100 b + 10 a + c) = 90 (a – b) = 90 ( c + 2 – c + 4) (use (i) & (ii) ) = 540 ∴ value decrease by 540