Analytical Puzzle #37 | GRE Big Book (Test #5 - Section #5 - Questions 11-13)

Directions: Each question or group of questions is based on a passage, graph, table, or set of conditions. In answering some of the questions, it may be useful to draw a rough diagram. For each question, select the best answer choice given.

A chemist has exactly four unlabeled bottles containing colorless liquids standing on a laboratory shelf. The chemist knows that the only six liquids that the bottles could possibly contain are pure X, pure Y, pure Z, or any mixture of two of these, and that no two bottles are filled with the same liquid. The only feasible way of testing for the identity of the liquids is to use strips of a special white reactive paper that turns red, blue, or yellow, depending on which of certain liquids it is dipped in. The full table of color changes and of the triggers for those changes is given below:

11) If none of the four liquids turns the reactive paper yellow, each of the following must be the contents of one of the bottles EXCEPT

(A) pure X
(B) pure Y
(C) pure Z
(D) Y mixed with Z
(E) X, Y, and Z mixed together

12) If the liquid in the first bottle tested turns the reactive paper red, and if the liquid in the second bottle tested turns the paper yellow, then a mix of some of the liquid from each of the first two bottles tested will turn the reactive paper

(A) red
(B) yellow
(C) either red or blue
(D) either red or yellow
(E) either blue or yellow

13) If the liquid in the first bottle tested turns the reactive paper red, and the liquid in the second bottle tested turns it blue, and if a mix of some of the liquid from each of the first two bottles tested turns it red, then which of the following must be true?

(A) The first bottle tested contains pure Y.
(B) The first bottle tested contains Y mixed with Z.
(C) The second bottle tested contains pure X.
(D) The second bottle tested contains pure Z.
(E) The second bottle tested contains Y mixed with Z.