One minute is left. Three questions have no answer written and you cannot do any of them. Nothing is taken off for a wrong answer. What should you do?
Hints
Take them one at a time. The first gives nothing away.
1A nudge
What does a blank score?
2The strategy
Compare the two outcomes. A blank scores zero for certain. A guess scores zero or more, and never less. Then ask how many questions that applies to.
3The full solution
A blank is worth nothing and a wrong answer is worth nothing, so a guess can only help. Fill in all three.
Solution— no shortcut on this one
A blank scores zero, guaranteed. A guess scores zero if wrong and full marks if right, and nothing is deducted for being wrong. So a guess is never worse than a blank and is sometimes better - which means every blank should be filled, not just the one you almost understand. With five choices, three guesses are worth about half a question on average, and that is half a question more than nothing. The transferable idea: on this paper, a blank is a decision to score zero.
Why this is on the test: Students leave blanks out of a sense of fairness that the scoring rules simply do not share, and it costs marks every single year.