Working in Section C

Hi all I am confused as to the length of working I am to do for the Section C questions. I am struggling with the typing and formatting, reading the questions and remembering what to type which is frustrating me. Question is however with workings such as question 100 in Kaplan revision kit.. car benefit etc. can this be done on one line or need it be extensive like in the answer format used in the book. I am taking soooo long to just type the working so dont know if just simple working can be used. Thanks