whats the OA?zareentaj wrote:How many different 7 digit members are their sum of whose digits is even ?
I am going to take a wild shot....
so we have 7 digits. _ _ _ _ _ _ _ and we need their sum to be even.
from 0-9, there are 5 even numbers (0,2,4,6,8) and you can add anyone to anyone, they'll give you an even number.
from 0-9, there are 5 odd numbers (1,3,5,7,9) and there are SOME combinations of these that will give you an even number. (1,3) (1,5) (1,7) (1,9) (3,5) (3,7) (3,9) (5,7) (5,9).
so the total # of options for each of the 7 digits we have is: 14.
so _ _ _ _ _ _ _ = 14^7
