The number of positive integers less than 10000 which contain the digit 5 atleast once is

5 men and 4 women are seated in a row. If the number of arrangements in which one particular man and one particular woman are together is $\alpha$ and the number of arrangements in which those two are not together is $\beta$, then $\alpha$ : $\beta=$

If a team of 4 persons is to be selected out of 4 married couples to play mixed doubles- tennis game, then the number of ways of forming a team in which no married couple appears is

An eight digit number divisible by 9 is to be formed using digits from 0 to 9 without repeating the digits. The number of ways in which this can be done is