In order to go from Greene to Semplain taking the fewest possible subway lines and making the fewest possible stops, ...

andreaskormusis on January 14, 2021

Stops

On this question, we are tasked with getting a passenger from G to S with the least stops. Were also told that every line runs both ways. U is connected to R and that trains travel both ways. So why is it that a person cannot go from G-R-U-S? It's the same amount of stops as going G-Q-U-S and it follows the same rules. Please explain what I'm missing here. If you take that route it's the same number of stops and it doesn't require you traveling through Q.

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shunhe on January 15, 2021

Hi @andreaskormusis,

Thanks for the question! Remember to read the question stem carefully! We are told to not only “make the fewest possible stops,” but also to “take the fewest possible subway lines.” G-Q-U-S takes fewer lines, since G-R-U-S requires taking L3. Thus, it wins out, and so you have to go through Q.

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

andreaskormusis on January 19, 2021

AHHHH there it is. Makes perfect sense. Thanks

shunhe on January 20, 2021

Glad I could help! Let us know if you have any further questions.