Question

HCF of which of the following pairs of numbers is not 1 1) 12,13 2) 12,14 3) 14,15 4) 20,29​

Answer 1

Answer:

Step-by-step explanation:

hcf of 12 and 14 is not 1 because hcf of 12 and 14 is 2

hence answer is option 2)

Answer 2

Option (2) is the correct option.
The numbers which have HCF not equal to 1 are 12 and 14.
The HCF of 12 and 14 = 2.

Highest common factor:

• As the name suggests the highest common factor between two numbers is defined as the highest number with which both the numbers are divisible.
• Both the numbers should be fully divisible by the HCF leaving a remainder equals zero.
• HCF of two numbers can be found by factorizing both the numbers into its smallest factor and then finding the common factor between both.

→ Option 1
   12, 13
  The only common number which divides both the numbers leaving
   remainder 0 = 1.

→ Option 2
  12, 14
  The common number which divides both the numbers leaving
  remainder 0 = 2.

→ Option 3
  14, 15
  The only common number which divides both the numbers leaving
   remainder 0 = 1.

→ Option 4
  20, 29
  The only common number which divides both the numbers leaving
   remainder 0 = 1.

∴ The numbers which have HCF not equal to 1 are 12 and 14.
⇒ Option (2) is the correct option.

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