Line 2 for the first question should be:

foreach(@this_array) {
[download]

... because @this_array and $this_array are different and unrelated variables.

And for the other question, line 2 should be:

%car_hash = reverse(%car_hash);
[download]

... again because $car_hash and %car_hash are different variables, but also because reverse() returns the reversed hash, so you need to assign it somewhere.

I'm surprised the exam questions contain such basic errors.