# Which one of the following could be true?

Jonathan on January 6, 2020

I understand why B is correct, was wondering if someone could explain the issue with A.

Replies

Skylar on January 21, 2020

@jwperez, happy to help.

(A) is incorrect because it violates Rule #4.

If Tape 1 has J on both sides and Tape 4 has F and H, that leaves the following variables to be placed in Tapes 2 and 3: F, H, R, R.

Rule #4 tells us that we cannot put F on a tape that is right after a tape with R, but there is no possible arrangement in this situation that would allow us to abide by that.

We know that we cannot put R on Tape 3 since (A) has F on Tape 4. However, if we put R on tape 2, we cannot put the remaining F on Tape 3. Because we have 2 R's left to place, we cannot pair them both with the one remaining F.

Does that make sense? Please let us know if you have any other questions!

on October 6, 2021

Well we can put the other F with R on 2 without violating any rules and put R and H on 3. Rule #4 says F cannot be one higher than R but they can be together. So I still do not see how answer choice A is wrong.