During a trial, an attorney is planning to call to the stand to testify six different witnesses - T, V, W, X, Y and Z. She will call each witness exactly one time and the order in which she calls them is subject to the following conditions:
The fourth witness must be T.
W and Y must both be called before V.
X must be called before W.
Which of the following could be the order in which the attorney calls the six witnesses ?

Options

A. W, X, Y, Z , V
B. X, Y, W, 7, Z, V
C. Z , T, X, W, Y, V
D. Z, X, W, T, K ,Y

Answer

C

Explanation

Begin "lt" is used to indicate before because the number of the witness called earlier will be lower than that of a witness called later, e.g., if X is alled first and W is called third, `XltW` because `1 lt 3`. The initial conditions do not determine any particular order, except that T must be fourth.
There is one further conclusion: since `WltV` and `XltW,XltV`. This further conclusion is the basis for the correct answer to Question 21.If you miss this further conclusion, when you get to Question 21, the fact that you don.t find a correct answer will prompt you to return to the initial conditions to look for it and this will consume some precious extra minutes.
This question does not provide any additional information. Attack it by applying each of the initial conditions to the choices, climinating impermissible orders until you are left with just one answer choice. That will be the correct choice.
The first condition specifies that T must be fourth and you can eliminate (4) on this score.
The second condition specifies that w and Y must both be called before V is called, and you can eliminate (2) and (5) on this basis.
you are left with choice (3), which must be correct. (3) does describe a possible order because it does not contradict any of the initial conditions.