Least Common Multiple

Welcome! You are encouraged to register with the site and login (for free). When you register, you support the site and your question history is saved.

What is the lowest positive integer that is divisible by every odd integer between 1 and 10?

Review: Least Common Multiple


Explanation

"Every odd integer between 1 and 10" includes 1, 3, 5, 7, and 9. To be divisible by all of these numbers, it must have as factors at least one 5, one 7, and two 3's (two so that the 9 is covered). This minimum set of factors multiplies to . Therefore, the answer is (B).

A side note: since the factors of 315 happen to be prime numbers (with the 9 counted as two 3's), we have found the prime factorization of 315. Repeatedly dividing a number in order to get its prime factorization is a technique always to keep in mind when confronting confusing situations around multiplying, dividing, factors, and primes.

Again, the correct answer is (B).


If you believe you have found an error in this question or explanation, please contact us and include the question title or URL in your message.