A question (please help)

Megadeth4168

The following is an example of a practice test I've taken but has really confused me.

You are creating a class A network with 8 subnets. What will the subnet mask be?

I've seen 2 different formulas.....

2^n-2
and
2^n

I don't actually use either of those methods for finding a subnet mask. Mine works just fine but the question did not specify usable subnets....

So my question is.... If I were to run across something like this on the test Would I assume usable or unusable subnets?

Megadeth4168

Thanks for the reply Darby! Every practice test I've taken so far is assuming usable. So I think you are right that I should assume usable on the real exam unless otherwise specified. I will be taking the exam sometime between now and the end of next week... Just waiting on my voucher code to come in. I'll let you all know how I do.

Once again thanks!