Hi woohoo921.
You can score Q47 - Q48 mostly by getting medium questions correct. In fact, you can score Q48 by getting as few as 17/28 counted quant questions correct. So, you can score Q48 while missing the 11 hardest quant questions you see.
I wouldn't go into the GMAT planning to miss 11 questions to score Q48, because you'd have to miss just the right 11 questions, but the point is that you don't have to get correct any of the super hard questions you see to score Q48.
Thus, you can prepare to score Q47 - Q48 by focusing on medium and medium hard questions, so 600- to 700-level questions and easier 700-level questions.
To learn more about how many questions you need to get correct to score 700+, see this post.
How Many Questions Wrong on the GMAT to get 700?