Certainly.

Each time an answer is given, see if it's right, then increment a counter. At the end, you'll have the number of right answers. The code below reads very much like that sentence:

# The code has already asked a question at this point 
# ("What is the answer to Life, the Universe, and Everything").
# The user has put in his/her answer.  
# The program has stored it in a scalar, $answer.
if ($answer == 42) { 
  $rightanswers++;
}
# Put that sort of logic in your question/answer loop, 
# then you can end with something like this:

if ($rightanswers == 25) {
  print "You got all of the questions right!  You win!\n";
}
elsif ($rightanswers > 20) {
  print "You got almost all of the questions right.  Not bad!\n";
}
elsif ($rightanswers > 10) {
  print "You could've done better...\n";
}
elsif ($rightanswers > 1) {
  print "You did quite poorly...\n";
}
else {
  print "Were you even reading the questions...?\n";
}
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