The price of a full–fare coach ticket from Toronto to Dallas on Breezeway Airlines is the same today as it was a year...

shunhe on July 20, 2020

Hi @Anna2020,

Thanks for the question! So let’s take a look at the stimulus. We’re told that taking inflation into account, the price of a full-fare coach ticket from Toronto to Dallas on Breezeway is the same as it was a year ago. But last year, it was 50% discounted tickets and 50% full-fare tickets. Now, it’s 90% discounted tickets and 10% full-fare tickets. So, the argument concludes, people pay less today on average than they did a year ago.

Now we’re asked for something that, if assumed, would make the conclusion logically follow. In other words, this is a strengthen with sufficient premise question. And we can think of ways to make the conclusion not follow, and then think about what kind of statement would help make the conclusion follow in those cases. And one thing that should jump out is that although we’re told that the tickets are discounted, we’re not told that they’re discounted the same amount. What if, this year, the tickets were discounted only by 5%, so you’re paying 95% of full fare, whereas last year, they were discounted by 50%, so you paid half of full fare? Well then the conclusion might not follow! So we need something to address this possibility .

Now let’s take a look at (B), which tells us that the discount tickets cost about the same today as they did a year ago. Well, if this is true, then the above scenario can’t happen! And if that’s the case, and the full-fare coach tickets stayed the same amount, and the discount coach tickets also stayed the same amount, then it has to be true that people are paying less on average for the ticket! And so (B) makes it so the conclusion has to be true, and is the correct answer.

(C), on the other hand, is wrong, though not because it’s a restatement of the premise. The stimulus tells us that the price of a full-fare coach ticket from Toronto to Dallas is the same today as it was a year ago. (C) gives us a bit more information by telling us that all full-fare coach tickets on Breezeway cost the same as they did a year ago (adjusting for inflation). So this would include, for example, Vancouver to Detroit. But the thing is that the information about these other tickets is irrelevant to the argument presented here, and so (C) doesn’t help make the conclusion follow and is wrong.

Hope this helps! Feel free to ask any other questions that you might have.