Sequences and recurrence relations

A tad curious about the order of these questions.
I am told.. see attached:

For a) Fairly straightforward. X₂ = k/2
b) it’s asking me to show X₃= 4/k …. Well, I only find X₃=2, so it would inform me that k=2 for part c)..
The issue is how do I express X₃=4/k.
I have X₃= k÷k/2....
Their solution was that X₃=2÷k/2 = 4/k, however if one unknown k=2, they must both be 2.
Wouldn't it make more sense for b and c to be the other way around? I don't know. It seems strange to know the the unknown value but only change one of the unknowns and leave the other unknown.
This is part of a engineering course I am doing.

Simply looks wrong, so either the recurrence relationship or x_3. Id contact the person who gave it to you, but someone must have noticed in the past?

I’m not sure. I’ve come across a few errors throughout the course, including wrong symbols to identify neutrons within the atomic structure. They’d put n^D instead of N⁰.
I’ve made a big list of stuff and informed them and they claim they’re going to be revamping stuff.
The course is recognised by universities, too. The company is called LearnDirect.
Also, their isotopes structure were wrong in the assignment I had to do. I had to provide references proving their errors and correct it for them lol. example- Calcium-42. They’d write ⁴²₂₀Calcium. I asked on here, too. To clarify.
Whether people have reported in the past, I am unsure but it’s a good thing that I’ve been studying A-Level and already know all the basic stuff. Instances like this make me realise I did learn something after all lol

I can sometimes guess what its supposed to be. About the only thing Id think of here would be
x_(n+1) = k / x_n^n
or something similar, but that would make the sum hard to evaluate.
A quick google from 2 months ago
https://www.reddit.com/r/HomeworkHelp/comments/1at8vz7/access_to_he_diploma_math_sequences_i_cant_work/