Q17

[ShehryarB30]

Could you pls explain this question

[ohthatpatrick]

Ideally, we do this by looking at The Tree we've created:

N.........K
...\..........\
J - M - G - O
.../
H - L

From this Tree, we can see
(A) nothing is to the left of K
(B) only O is to the right of G
(C) YES. M, G, O, and L are to the right of H
(D) Only M, G, and O are to the right of J.
(E) Only J, N, and H are to the left of M.

If we didn't know how to write and read a Tree, we would just try to write counterexamples, as we always do on must be true.

(A) K N H L J M G O is legal, so there doesn't HAVE to be something before K.
(B) from that same scenario, we just proved that there don't HAVE to be two things after G.
(D) from that same scenario, we just proved that there don't HAVE to be four things after J.
(E) N H J M G K O L is legal, so there doesn't HAVE to be four things before M.

Notice how even though plug and chug takes more work, you usually get lucky and don't have to write four separate scenarios. Some of the ones you'll write will often be ammunition for multiple answers.