Machine-translated by Google. Questions are authored in English.
Top

Discussion

Consider the following pairs:

1.A number divisible by 2 and 3Divisble by 6
2.A number divisible by 4Divisble by 8
3.A number divisible by 5 and 10Divisible by 10

How many of the above pairs are correctly matched?

  • A.Only one pair
  • B.Only two pairs
  • C.All three pairs
  • D.None of the pairs

Answer: B

Only two pairs are correctly matched.

Pair 1 is right: 2 and 3 are coprime, so a number divisible by both is divisible by their product, 6.

Pair 2 is wrong: 4, 12 and 20 are divisible by 4 but not by 8. Divisibility passes down to factors, not up to multiples.

Pair 3 is right: the condition already includes divisibility by 10, and divisibility by 5 adds nothing, because 5 is a factor of 10. Note that the rule in pair 1 does not extend to non-coprime pairs: divisible by 2 and 4 does not mean divisible by 8.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.