Having just sat through a string of JAR modules I think I can answer you this one !
What you have to look out for when you are surfing for questions and answers is that you must take the worded questions with a pinch of salt. You'll find quite often a badly remembered question can lead you up the garden path. There is no substitution for getting stuck into the study books !
Enough waffle - 2 x 12v,40aH Batteries in parallel = 12v,80aH