Answer:
Xiomara can make 15 necklaces, with 3 blue, 4 red, and 2 green stones on each necklace.
Explanation:
We wish to find the greatest common divisor (GCD) of 45, 60, and 30, since each necklace must have an equal number of stones. Using the Euclidean algorithm (or just plain common sense), the GCD is 15. Thus, Xiomara can make 15 necklaces at most, with each of them containing 3 blue stones, 4 red stones, and 2 green stones.