This means that the temperature-volume fraction will always be the same value if the pressure and amount remain constant. Let T 1 and V 1 be a temperature-volume pair of data at the start of an experiment. The new temperature-volume data pair will preserve the value of k. We do not care what the actual value of k is, only that two different temperature-volume data pairs equal the same value and that value is called k. This graphic simply restates the above in a way HTML cannot do.
Some people remember one better than the other, so both are provided.
Now, please don't send me e-mail asking me what I meant by that. Remember that you have to plug into the equation in a very specific way. The temperatures and volumes come in connected pairs and you must put them in the proper place. First of all, 2.20 L is the wrong answer. Sometimes a student will look at the temperature being cut in half and reason that the volume must also be cut in half.