You might wana attack this in those steps. I'd try NOT to give straight answers but rather help you think

**Step 1. Logically subnet the departments you have.**
You said you need a Class A network address. Even if you do that, you can still subnet the network with a /24, /25, /26... etc masks. Why?, because you said you want VLSM, and VLSM is classless. In otherwords, you can use

**any** subnet mask as long your networks don't overlap.

So lets take the network say 10.1.1.0/24 (i.e 10.1.1.x). You obviously need to subnet that. The following are all possible subnet masks.

**Borrowing 0 bits**: gives a subnet mask of 255.255.255.0 which gives you 1 network with 253 hosts

**Borrowing 1 bits**: gives a subnet mask of 255.255.255.128 which gives you 2 networks with 126 hosts each

**Borrowing 2 bits**: gives a subnet mask of 255.255.255.192 which gives you 4 networks with 62 hosts each

**Borrowing 3 bits**: gives a subnet mask of 255.255.255.224 which gives you 8 networks with 30 hosts each

**Borrowing 4 bits**: gives a subnet mask of 255.255.255.240 which gives you 16 networks with 14 hosts each

**Borrowing 5 bits**: gives a subnet mask of 255.255.255.248 which gives you 32 networks with 6 hosts each

**Borrowing 6 bits**: gives a subnet mask of 255.255.255.252 which gives you 64 networks with 2 hosts each

Q: Which subnet mask you would choose for the Warehouse (62 PCs)?

A: 255.255.255.192. Why? because choosing 255.255.255.224 or lower will not have enough hosts for you. And choosing 255.255.255.128 or higher will waste the number of hosts.

Q: Now you tell me which subnet mask you would choose for the Sales (48 PCs)? Hint: choose the best fit.

Now once you choose the subnet masks for all networks (including the 2 servers networks), you need to put a different network address for each of the networks. So the network bits need to be different for each. For example:

Warehouse: 10.1.1.0, mask: 255.255.255.192.

Net2: 10.1.1.64, mask 255.255.255.248

Net3: 10.1.1.72, mask 255.255.255.248

Net4: 10.1.1.76, mask 255.255.255.252

The above is NOT your answer

just an example. When you decode the above to binary you will see that each has a different network address and that they don't overlap. For more info I recommend reading here:

www.firewall.cx/ip-subnetting-basic-concepts.php
**Step 2: Physically define and layout the network.**
The question only implies performance and costs issues. So I'd try to minimize the number of devices/switches/routers as much as possible. And reduce the number of links required to reach from,to any 2 points.

The minimum I could see is 3 switches, one for each department. And a 4th small switch for the two servers. All switches connected to a central router. Cisco switches usually come in either 24 or 48 ports. There are other higher ones but they cost more. The 2950 series for example supports VLANs. You could google for the prices.

For the Warehouse switch, if you can't find a single switch with 62 ports or more you could purchase two smaller switches and connect them via a trunk. The 2 servers small switch could be any brand with FastEthernet or better GigabitEthernet ports. There are further details here, but I'll leave that for you....

**Step 3: Implement the configs**
Tell us when you reach this point. If you need more help.

I hope this helps and does not confuse.