The hidden presence of CIDR (Classless Inter domain routing) in EGE Informatics (example of problem 12 from Trial KIM)

   Answer is obviously  3*8+2 = 26 due to 60 = 00111100 (binary)
   Thus we may place "11"  in first two bits of fourth octet of  network mask

   What means CIDR - See http://www.zvmpt.ru/IP_NGN/praktika/praktika_8.htm
  

   

  
   On the other hand it is easy to see how 162.232.136.0/26 looks