If all the numbers which are greater than 6000 and less than 10000 are formed with the digits, $3,5,6,7,8$ without repetition of the digits, then the difference between the number of odd numbers and the number of even number among them is

A man has 7 relatives, 4 of them are ladies and 3 gents; his wife has 7 other relatives, 3 of them are ladies and 4 gents. The number of ways they can invite them to a party of 3 ladies and 3 gents so that the there are 3 of man's relatives and 3 of wife's relatives, is

All the letters of word 'COLLEGE' are arranged in all possible ways and all the seven letter words (with or without meaning) thus formed are arranged in the dictionary order. Then, the rank of the word 'COLLEGE' is

If all the possible 3-digit numbers are formed using the digits $1,3,5,7$ and 9 without repeating any digit, then the number of such 3 -digit numbers which are divisible by 3 is