Hi, if you know how to solve this problem and you can explain your answer. Please let me know. Also, if you know any shortcut method regarding this question, please let me know too.
I have already looked at the following link, but I still do not get it. http://www.gmatclub.com/forum/t22425
gmatperp_question.GIF [ 5.22 KiB | Viewed 586 times ]