Understanding redemtion yield

The questions are selected at random from a bank of questions, and so I have no idea which question you are referring to. Have you watched all of the free lectures? Because everything you have asked is covered in detail in the lectures - they are a complete free course for Paper F9 and cover everything needed to be able to pass the exam well. The workings do appear after you finish the test - they appear at the bottom of the screen after you have pressed the review button.