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