Correct Answer - 300
Since, each box can hold five balls. `therefore` Number of ways in which balls could be distributed so that none is empty, are (2, 2, 1) or (3, 1, 1),
i.e. `(""^(5)C_(2) ""^(3)C_(2) ""^(1)C_(1) + ""^(5)C_(3) ""^(2)C_(1) ""^(1)C_(1)) xx 3!`
`= (30 + 20) xx 6 = 300`