## Q20

ShehryarB30
Elle Woods

Posts: 100
Joined: July 07th, 2018

### Q20

Could you pls explain this question?

ohthatpatrick
Atticus Finch

Posts: 4259
Joined: April 01st, 2011

### Re: Q20

From the setup, we had this:
...........R
........./
...[ ? ]
........\
...........S ---> [ ? ]

And then we had rules that said:
[ R/T ] ---> Q
[ T/U ] ---> P

So if T doesn't lead to anything else, then we know that the two above rules will look like this:
R --> Q
U --> P

And if we combine those with our S/R rule, we now have
...........R ---> Q
........./
...[ ? ]
........\
...........S ---> [ ? ]

Who is the question mark that is leading to R and S?

It can't be Q, because Q comes after R.
It can't be T, because T doesn't lead anywhere on Q20.
It can't be U, because U leads to P, and you're not allowed to lead to three things (P, R, and S)

So it would have to be P. Thus, we'd have this
...........R ---> Q
........../
U -> P
..........\
...........S ---> [ ? ]

Where does T go? It has to go into the empty spot after S.

...........R ---> Q
........../
U -> P
..........\
...........S ---> T

(A) correct
(B) opposite
(C) U only transmitted to P
(D) P transmitted to R and S
(E) R transmitted to Q