Question

hcf for 285 and 1245

Answer 1

Hi!

Here is the answer to your question.

 

Since on dividing 285 by the required number, the remainder is 9.

∴ 285 – 9 = 276 will be exactly divisible by the required number.

Similarly, 1249 – 7 = 1242 will be also exactly divisible by the required number.

∴The required number is HCF of 276 and 1242.

Prime factorization of 276 = 2×2×3×23

Prime factorization of 1242 = 2×3×3×3×23

HCF of 276 and 1242 = 2×3×23 = 138

Thus, the required greatest number which divides 285 and 1249 leaving remainders 9 and 7 respectively is 138.

Answer 2

Here is your answer :

1245 = 285 × 4 + 105

285 = 105 × 2 + 75

105 = 75 × 1 + 30

75 = 30 × 2 + 15

30 = 15 × 2 + 0

So the H.C.F is 15