The largest 6-digit number that can be formed using the digits 3, 9, 0, 4, 5 and 5 is
955430
To form the largest number using the digits 3, 9, 0, 4, 5 and 5 we need to arrange the numbers in descending order.
9 > 5,5 > 4 > 3 > 0
Arranging the digits in descending order we get 9, 5, 5, 4, 3 and 0.
Hence, the largest 6-digit number that can be formed using the digits 3, 9, 0, 4, 5 and 5 is 955430.