Sasha can complete 15 questions an hour. If she has 60 questions to complete and she works for 2 hours, how many questions does she still need to complete? Think carefully first, then make a decision:
Sasha completes 15 questions / hour * 2 hours = 30 questions. This means there are still 60 questions 30 questions = 30 questions left to complete. So, the answer is 30.