jmc

A pot will have 3 different colored balloons on it if it is a multiple of 4, 6, and 10. Thus, we must first find the LCM of 4, 6, and 10. $4=2^2$, $6=2\cdot 3$, and $10=2\cdot 5$. For a number to be a multiple of all three of these numbers, it prime factorization must have a 2 raised to at least the second power, a 3 raised to at least the first power, and a 5 raised to at least the first power. Thus, the least common multiple is $2^2\cdot 3\cdot 5=60$. Thus, every 60th pot will have 3 different colored balloons on it. Because there are 600 total pots, the number of pots with 3 different colored balloons on it is $600÷60=\boxed{10}$.