How many numbers greater than 300 000 are there using only the digits 1, 1, 1, 2, 2, 3?

Answer 1

clearly the first digit must be the 3, so there are only the other 5 digits to arrange.
we have 3 alike of one kind and 2 alike of another,
so the number of ways = 1(5!)/(3!2!) = 10