Ang, Ben, and Jasmin each have 5 blocks, colored red, blue, yellow, white, and green; and there are 5 empty boxes. Each of the people randomly and independently of the other two people places one of their blocks into each box. The probability that at least one box receives 3 blocks all of the same color is m/n, where m and n are relatively prime positive integers. What is m + n?
Already know the answer so I'm only interested in the solution