(D) Y, X, Z (E) Z, X, Z
13. If points O and Z are just meeting at the point of contact between the dials, and if dial 1 spins at the same speed as dial 2, what is the smallest number of revolutions of each dial that will bring O and Z together again?
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5
14. If points N and Y are just meeting at the point of contact between the dials, and if dial 1 spins at the same speed as dial 2, which of the following pairs of points will also meet in the course of the next full revolution of the dials?
(A) N and Z (B) O and X (C) O and Z
(D) P and X (E) P and Y
15. Which of the following is a possible sequence of pairs of points meeting consecutively at the point of contact between the dials if dial 1 spins at the same speed as dial 2?
(A) N and O followed by X and Z
(B) N and X followed by O and Z
(C) O and X followed by N and X
(D) O and Y followed by N and Z
(E) P and Z followed by P and X
16. If points P and X are just meeting at the point of contact between the dials, and if dial 2 spins at exactly double the speed of dial 1, which of the following pairs of points will be the next pair to meet at the point of contact?
(A) N and Y (B) N and Z (C) O and X
(D) O and Z (E) P and Y
17. If points P and Y are just meeting at the point of contact between the dials, and if dial 1 spins at exactly three times the speed of dial 2, which of the following pairs of points will be the next pair to meet at the point of contact? (A) N and X (B) N and Z (C) O and Y (D) P and X (E) P and Z
Questions 18-22