Answer:
210
Explanation:
When finding the LCM(least common multiple) you need to factor each number into the product of prime number also called finding the prime factorization. Both 7 and 3 are prime, so they do not need to be factored further. However, 10 can be factored into 5 x 2.
3 - 3
7 - 7
10 - 5 x 2
By looking at the factors above, you notice none of them are the same, so none of the numbers share factors. This means you can just multiply all the factors to get the LCM:
3 x 7 x 5 x 2
210