Question 53
Maria has three red coins and one blue coin, all of the same radius and with rubber edges. She puts the red coins on a table at the vertices of an equilateral triangle so that each touches the other two. She then places the blue coin on the table touching a red coin. Keeping the red coins fixed, she rolls the blue coin so it always touches at least one red coin and the rubber edges do not slip. After one complete circuit around the three red coins, the blue coin returns to its starting point. How many turns has it made about its own centre?
(A) 3 (B) 1 (C) $\pi$ (D) $3\pi/4$ (E) $9/2$.
(A) 3 (B) 1 (C) $\pi$ (D) $3\pi/4$ (E) $9/2$.