Arun
Last Activity: 6 Years ago
Dear Palak
n can be of the form of
i) 4n
ii) 4n + 1
iii) 4n + 2
iv) 4n + 3
Now using 1st case
4n, 4n+ 3, 4n + 6 , 4n + 9
Only 4n is divisible by 4
Now using 2nd case
4n + 1, 4n + 4, 4n + 7, 4n + 10
Only 4n + 4 = 4 (n+1) is divisible by 4
similarly you can do this for rest of the cases and find that only one number is divisible by 4
Regards
Arun (askIITians forum expert)