Question #1038

Sufficient vs necessary

Started by AndrewArabie · started 2022-07-07 01:41 · last activity 2022-07-09 16:56 · 1 reply

There was an earlier question describing how "unless" should indicate a necessary condition but it doesn't here. I don't think that one was sufficiently explained. Next, in the video, the narrator says "New Buildings" is a necessary condition is in the third and fourth sentence but that does not appear to be the case because it can be rephrased "If new buildings, then overcrowded schools." Next, she says "new taxes" are a sufficient condition in the second to last sentence which again, seems wrong because it can be rephrased, "if more roads, then new taxes." I understand that I am wrong and misunderstanding this, but I cannot see how. By the way, I am getting the question right, not because I can rule out C and D, but because the correct answer just seems *most* correct.

Replies

Emil-Kunkin · 2022-07-09 16:56

Hi AndrewArabie, Let's work through this question statement by statement. We are told that unless BT, then approved. That means that if they do not band togather, than the zoning will be approved. So, If Not BT -> Approved (If Approved -> Not BT) We also know that approval is necessary for the city to be able to build new buildings. so If Not approved- Not NB (If NB -> Approved) We are then told that these new building will lead to new roads and overcrowded schools (indirectly), so IF NB -> New roads/OCS (If no new roads/no OCS -> No NB) And finally, we know that New roads and schools are impossible without tax increases, so IF NR/new schools -> New taxes. We can then follow this causal chain all the way from NB to New Taxes: If NB -> New roads If NR/new schools -> New taxes