Mateo and Ivy are building towers made of blocks. Mateo is building a tower 9 blocks at a time, and Ivy is building a tower 15 blocks at a time. How many blocks high do both of their towers need to be for them to be the same height?

Answer 1

To find the height of the towers, we need to find the least common multiple of 9 and 15.
Prime factorize 9: 3 * 3
Prime factorize 15: 3 * 5
The least common multiple of 9 and 15 is 3 * 3 * 5 = 45.
Therefore, both towers need to be 45 blocks high. Answer: \boxed{45}.