Hi Mavis, its good of you to be mature enough to explain yourself. Having never posted any questions on this App, at least I now know the description linked to the upvote/downvote. :) I typically post the fastest solution first, as it takes up the least of my time. May not have time to pen out the simplest solution... but you are fortunate this is the post exam period. Please try to solve the question based on the reasoning steps here. If still unable to solve, refer to the next picture.