#21 - Global

[Administrator]

Please post below with any questions!

[ClaudiaK32]

I chose B for this answer and am unsure for why C is correct.

[Charlie Melman]

Hi Claudia,

Answer choice (B) is incorrect because there is one setup where Q pushes the virus to two other computers. If Q is the piece that transmits to R and S, and T is the piece that transmits to Q (as the rules allow), then it's entirely possible to construct a situation that does not violate any of the rules.

But in answer choice (C), you can't satisfy the second-to-last and last rules at the same time, while also making R transmit to two other computers. You can satisfy one of the two, but not both.

I hope this makes sense!

[Ari]

I am having a hard time with this. I also chose B. I tried to work out the problem as Charlie explained where T receives the virus, and transmits it Q, which transmits it to R and S. However, S has to transmit it to one computer and we are left with U and P. P has to receive the virus from T or U, so S must transmit the virus to U, but now where does P go? What am I missing here that would resolve my issue? Otherwise, I do not see how Q would not be correct. I do see why R is correct, but I just can't seem to create a diagram to make Q incorrect. Below is my replication of the diagram described above.

--- R --- P (wrong)
Virus --- T -- Q
--- S --- U

Hi Claudia,

Answer choice (B) is incorrect because there is one setup where Q pushes the virus to two other computers. If Q is the piece that transmits to R and S, and T is the piece that transmits to Q (as the rules allow), then it's entirely possible to construct a situation that does not violate any of the rules.

But in answer choice (C), you can't satisfy the second-to-last and last rules at the same time, while also making R transmit to two other computers. You can satisfy one of the two, but not both.

I hope this makes sense!

[Ari]

Never mind! I was reading the 2nd rule to mean that S could only transmit it to one and that was the end, but you could have
S --- U --- P and R does not transmit it to any computer.

I am having a hard time with this. I also chose B. I tried to work out the problem as Charlie explained where T receives the virus, and transmits it Q, which transmits it to R and S. However, S has to transmit it to one computer and we are left with U and P. P has to receive the virus from T or U, so S must transmit the virus to U, but now where does P go? What am I missing here that would resolve my issue? Otherwise, I do not see how Q would not be correct. I do see why R is correct, but I just can't seem to create a diagram to make Q incorrect. Below is my replication of the diagram described above.

--- R --- P (wrong)
Virus --- T -- Q
--- S --- U

Hi Claudia,

Answer choice (B) is incorrect because there is one setup where Q pushes the virus to two other computers. If Q is the piece that transmits to R and S, and T is the piece that transmits to Q (as the rules allow), then it's entirely possible to construct a situation that does not violate any of the rules.

But in answer choice (C), you can't satisfy the second-to-last and last rules at the same time, while also making R transmit to two other computers. You can satisfy one of the two, but not both.

I hope this makes sense!

[kupwarriors9]

Can someone tell me why my thought process was wrong? I had originally thought the answer would be T or U - not R.

U P R Q S T

Thus, couldn't have R transmitted the virus to two other computers (S and T)?

[Robert Carroll]

kup,

It's impossible to R to transmit to S. R and S receive the virus from the same computer. In order for R to transmit to S, R would have to transmit to itself, which is impossible.

Robert Carroll

[christinecwt]

Hi All, can anyone explain why R can send to two more coputers (such as U and P). Many thanks!

[bebeg3168]

Hi All, can anyone explain why R can send to two more coputers (such as U and P). Many thanks!

Hi Christinecwt,
I believe the 3rd rule eliminates the possibility. I missed this one too. Hope this helps

[Paul Popa]

Hi All, can anyone explain why R can send to two more coputers (such as U and P). Many thanks!

Hi Christinecwt,
I believe the 3rd rule eliminates the possibility. I missed this one too. Hope this helps

Hi Christine and Bebe,

A combination of rules 2, 3, and 5 ultimately render it impossible for R to transmit the virus to two computers. We have six computers to play with, and one has to be the computer that transmits the virus to R and S. We also need S to transmit the virus to one (and only one) other computer. These rules force four of the computers into a placement already. We then see from rule 5 that only T or U can send the virus to P, so while we can have R transmit the virus to Q, for example, we would need to build a chain off of S to satisfy that last rule. Hope this helps!