[machiaweliczny]

I'm sorry to say this - but given this examples I wouldn't hire you if you can't solve so simple stuff.

You have probably problems with text comprehension because I don't know how you can't solve it.

It's not coding that's needed - you should be able to do it on "paper".

What are you really struggling with?

1) understanding problem setup (reading)

2) coming with solution to problem (search)

3) implementing solution in programming language (coding)

[gambiting]

I have to agree with you. Especially the ceasar cipher example is literally about following the steps, everything is outlined in an almost step-by-step fashion. The only part of the exercise that might be new to OP is programming in C - but the algorithm itself is stupidly well explained and the bullet points literally tell them what to do. It's as if they read the first paragraph and decided it's some arcane voodoo magic so it's not worth reading any further.

[StrLght]

It might sound a little bit too harsh, but I totally agree with you. Furthermore, provided examples are missing search step – there's no need to come up with solution, because solution is explicitly specified in task description.