IAS21 foreign transactions and entities

Good afternoon,
I found the example for foreign currency really helpful and the explanation very clear. I have a doubt though. I was trying to work through some of the questions in the bpp book and I have got really confused. They seem to be working out SC with the exchange rate at date of acquisition of subsidiary and also RE pre-acq and post -acqu differentely from cR. My understanding is that any items within the Statement of Financial Position are to be translated as per CR. Could you please clarify, it would be most helpful . The question I am referring to is one called “Jennie and Bennie”

Thanks so much in advance.