Question

Started by Steph · started 2019-02-05 03:52 · last activity 2019-02-09 22:51 · 3 replies

Can I see an explanation for this question without using the GURU method?

Replies

  1. Ravi · 2019-02-05 08:25

    @Steph, Happy to help. The best way to answer this question is to make sure that your game setup is solid. This is a question that rewards you for doing work up front and can be answered very quickly if you've made the necessary deductions after reading the rules. We're told Flyaway owns two planes: P and Q, and Getaway owns exactly three planes: R, S, and T. F: P, Q G: R, S, T Each plane makes one flight. Rule 1 says only one plane departs at a time. 1) _ _ _ _ _ Rule 2 says each plane makes either a domestic or an international flight, but not both. 2) i - >/d d - >/i /i - >d /d - i Rule 3 says P makes an international flight 3) Pi Rule 4 says Q and R make domestic filghts 4) Qd, Rd Rule 5 says all international flights depart before any domestic flight 5) i-d Rule 5 is crucial because it allows us to make some inferences. With Rule 5, we know that Pi must go before both Qd and Rd Rule 6 says any Getaway domestic flight departs before Flyhigh's domestic flight. Rule 6 makes us know that Rd must go before Qd, so now we have Pi - Rd - Qd We only have 2 pieces left to map, S and T. We can make two separate boards that show what would happen if S and T were i or d, respectively. If S and T are d and i or i and d, we can just use the parts from each setup that have them in those places and combine them into a new map. For simplicity, it's best to just write out the two separate scenarios with S and T both being i or d so that we have less clutter on the page. If S and T are both i, then rule 5 triggers, so we know that they must both go before Rd, which must go before Qd Pi - Rd - Qd Si - Rd - Qd Ti - Rd - Qd If S and T are both d, then they will be on par with Rd but will still be before Qd because they are Getaway flights and all Getaway domestic flights go before Flyhigh's domestic flight Pi - Rd - Qd Pi - Sd - Qd Pi - Td - Qd In both of these worlds, Qd is last, so we know that Qd must go 5th on the board _ _ _ _ Qd The question asks us how many planes could depart 2nd. We know Q is out, so (E) is out as well, giving us four answer choices left. Looking at our scenarios, in our second one we see that Rd, Sd, and Td would all go after Pi but before Qd. However, Rd, Sd, and Td have no order hierarchy with respect to each other, so this means that any of them could go 2nd after Pi. This means that at least 3 of the game pieces could go 2nd. Now, let's see if P could go 2nd. In our first scenario, Pi, Si, and Ti all have to go before Rd - -Qd. However, there is no hierarchy of order with respect to Pi, Si, and Ti, so Pi could go second after either Si or Ti. This means that 4 of the 5 pieces could go 2nd, so (D) is our correct answer. Does this make sense? Let us know if you have any more questions! 6)
  2. Steph · 2019-02-09 15:28

    Thanks! Makes sense.
  3. Ravi · 2019-02-09 22:51

    @Steph happy to help!

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