For VWO and H/V classes.
About the Challenge path:
+ Did you score high for the first tests?
Then you are invited to try the Challenge path,
doing C4 and C5 on p.135 ! (Of course everybody may try!)
+ However, C4 is a real challenge, especially C4b. This is about calculating
precisely. The Solutionsbook does not make it much easier, I think. (All the
more as it contains a mistake.)
So this is a REAL CHALLENGE!