You have to simplify 18 and 40: divide each number by 2, and you get 9 and 20. For every 20 questions, Mathew gets 9 right. Now, you multiply 20 questions by 3 to get the second part of the problem, 60 questions. Because you multiplied 20 by 3, you do the same with 9. 9 x 3= 27. For every 60 questions, Mathew gets 27 right.
