Meng attended a Chinese Competition which had $60$ questions. Meng answered $70 \%$ of them. For each correct answer, Meng will get $3$ marks. However, for each wrong answer, Meng will deduct $1$ mark. For each unanswered question, no marks will be awarded nor deducted. If Meng scored $78$ marks in total, how many questions did Meng answer correctly? 
Overseas Competition->Knowledge Point->Word Problem Modules->Chicken-Rabbit Problems