Afour digit number (with no repetitions) is to be formed from the set of numbers {0,1,2,3,4,5,6,7}. find the probability that the number
a) is even
b) is odd
c) is less than 4000
d) is less than 4000, given that it is greater than 3000

Even #  if it ends with 0, # of ways = 6*5*4 = 120 if not, 3 ways for ending digit, 5 ways for 1st digit, 5*4 for middle digits = 300 
so total ways = 420 
odd #  4 ways of ending digit, 5 ways for 1st digit, 5*4 for middle digits = 400 ways 
< 4000:  3 ways for starting digit, 6*5*4 ways for remaining digits = 360 ways 
> 3000 & < 4000  1 way for starting digit , 6*5*4 for remaining digits = 120 ways 

It says in the questions that it is 6.5?