Question: is 50 a factor of 30?
Answer: The factors of 30 are 30, 15, 10, 6, 5, 3, 2, 1. The factors of 50 are 50, 25, 10, 5, 2, 1. The common factors of 30 and 50 are 10, 5, 2, 1, intersecting the two sets above. In the intersection factors of 30 ∩ factors of 50 the greatest element is 10.