The answers:

1. Hex value aC4 into decimal

This means we have...

"a" units of 256

"c" units of 16

"4" units of 1

In hex, "a" is 10 and "c" = 12. Therefore, we have ....

10 units of 256 = 2560

12 units of 16 = 192

4 units of 1 = 1

Add them up and you get 2756.

By the way, get used to doing these conversions and additions by hand -- you can't use the Windows calculator in the exam room.

2. Decimal 1092 into hex

First question: Are there units of 256 in this value? Sure, there are actually four of them...

4 x 256 = 1024

Subtract that from 1092 and we have 68 left. Are there units of 16 in 68? Sure, there are 4 of those as well.

4 x 16 = 64

That leaves us 4, which is four units of 1.

Our hex value: 444

3. Binary string 00110010 into decimal

Going from left to right, the following bits are set to one -- 32, 16, and 2. Add them up and you have 50.

4. Binary string 11001101 into hex

A little more work is needed here, but not much. ;)

These bits are set to one: 128, 64, 8, 4, and 1. Add them up and you have 205.

Converting to hex, we obviously don't have any units of 256 in there. We have plenty of 16s, though - twelve of them.

16 x 12 = 192 (12 = "c"

We have 13 remaining, which in hex is "d" - so the resulting hex value is "cd".

5. Hex value C8 into binary

Converting that to decimal, we have 200 -- and you can probably convert that in your sleep at this point.

But just in case you're not sleeping, that binary string would have the 128, 64, and 8 bits set, resulting in:

*11001000*