September 2016 LSAT Section 3 Question 23
If P is the only computer that transmitted the virus to two other computers on the network, which one of the followin...
3 Replies
Ben on December 18, 2019
Hi Ryan, thanks for the question!The idea is that if P is the only computer that transmits to two others, then it must transmit to both R and S. This is because R and S must get the virus from the same computer.
Then we have two options that can give the virus to P. This is computers T and U. We can create two diagrams. One in which T - P. One in which U - P.
So now we have the following:
T - P - R and S, (in this scenario, R must give the virus to Q because T cannot anymore. So R gives it to Q and S gives it to U)
U - P - R and S (in this scenario, S must give the virus to T because it cannot give it to the leftover Q. The remaining Q can receive the virus from R or T)
This gives us 3 diagrams to answer our question.
T - P - R - Q
- S - U
U - P - R - Q
- S - T
U - P - R
- S - T - Q
In all scenario, Q is last (answer choice C)
Answer choice A is incorrect because it is possible that S transmits the virus to U. (First diagram).
I hope this helps. Please let me know if you have any other questions!
on June 24, 2020
How do you know that a computer must give it to P? Couldn't there be more diagrams if P was the first infected? or am I overlooking a rule here?on June 24, 2020
Nevermind.