In a competitive exam, there are 70 questions. Students can score 4 marks for each correct answer while 1 mark is deducted for each incorrect answer. If Tania answered 9 questions correctly, how many marks did she get?

Tap A can fill a tank in 6 hours, while tap B can empty the full tank in 9 hours. If both taps are open together, how long will it take to fill an empty tank?