If they took 12 quizzes over the course of 2 weeks, then we can assume that they take 6 quizzes each week (12/2 = 6).
Over the course of 5 weeks, they'll have taken 30 quizzes if the above is true. However, the 'or' is there because I don't know if they're including the past 12 or not. If they are including the 12 quizzes taken over 2 weeks, then the answer is 42. If they are only referring to the 5 weeks of school, then the answer is 30.
To rock to the nearest ten and hundred if his 15 or of your round on time if it's less you round down same with the hundreds like if it's 150 rooms and it's all so different with decimals