25) How many 4-digit numbers greater than 7000 can be formed from the digits 1,2,3,5,7,8,9, if repetition is not allowed?

27) How many 4-digit numbers greater than 3400, can be formed from the digits 1,2,3,4,5,6,7 if repetition is not allowed?

28) How many 5-digit numbers, divisible by 5, can be formed from the digits 3, 1, 7,0,9,5 if repetition is not allowed?

29) How many 5-digit numbers, not divisible by 5, can be formed from the digits 3, 1, 7,0,9,5 if repetition is not allowed?

30) How many numbers between 3000 and 4000, divisible by 5, can be formed from the digits 3, 4, 5,6,7,8 if repetition is not allowed?

86) Number of words which can be formed from the letters a,b,c,d,e,f taken 3 at a time, each word containing at least 1 vowel, is