To find the largest number which divides 129 and 545 leaving remainder 3 and 5 i.e. HCF.
Consider HCF be x.
In order to make 129 and 545 completely divisible by x, we need to deduct the remainder 3 and 5 from the cases.
126 =2× 3 x 3 x 7
540= 2×2×3×3 x 3 x 5
⇒ x = 2×3×3 = 18
∴ largest number which divides 129 and 545 leaving remainder 3 and 5 in case is 18.