On if/then questions, identify the contrapositive of the statement and then locate it among the answer choices. The answer choices
will contain a number of tempting wrong-answer traps.
Here, you are told that if Carlos follows the safety precautions, his experiment will go according to plan. The contrapositive of this
statement is that if Carlos’s experiment did not go according to plan, then he did not follow the safety precautions. You should see
that this is choice (C).
Choices (A) and (B) might be true. They do seem logical. However, we don’t know that they must be true. The fact that his
experiment will go according to plan if he follows the safety precautions does not mean that it could not go according to plan if he
didn’t follow them. That’s too big a leap to make. The issue of danger is beyond the scope of the argument. You might assume that
the experiment is potentially dangerous, but you do not know this. (D) is too extreme—just because following the safety precautions
will lead to a successful experiment does not mean that this is the only thing that will work. This is the same reasoning that
eliminates (E)—you simply do not know what will happen if Carlos fails to follow safety precautions. You only know what happens
if he follows them.