Question

An organization is granted a block; one address is 2.2.2.64/20. The organization needs 10 subnets. What is the subnet prefix length?

Answer 1

Because you already have a slash 20, you need 10 subnets.

So, you can go to the properties of 2 (2-4-8-16-32, etc.) 8 is too small and 32 is too big. So, I choose 16. I need 2 ^ 4 bits to get 16 subnets.

So, I already add 4 bits on 4 and finish with slash 24.

An institution 2.2.2.64/20 will not be given

It can be given 2.2.0.0/20, which will be 2.2.0.1 - 2.2.15.254. Thats give you 40 9 4 IPs to play you.

You can break it in small subnets with / 24

2.2.1.0/24

2.2.2.0/24

2.2.3.0/24