Chapter 69: A Sister from a Different Father and Mother Time quickly flew by, and soon it was Friday. In the afternoon. Jiang Ning put in a lot of effort to secure a half-day leave from Yang Mei's supervisor. The price? She had to place in the top five of next month's math competition at school and represent the school in the city's Olympiad contest alongside other high school students. To be honest. If it were just a competition among first-year students, getting into the top five wouldn’t be a…