Eight figure skaters -four women: Fiona, Gloria, Heidi, and Jill; and four men: Ravi, Shigeru, Toby, and Vernon-will participate in a one-day skating exhibition consisting of four consecutively performed sets - set 1 through set 4. Each set will be performed in exactly one pair of skaters, one man and one woman. Each skater will perform by exactly one of the sets, subject to the following constraints:
Ravi skates in an earlier set than Vernon does.
Fiona skates in either set 1 or set 4.
Jill does not skate with Toby.
Shigeru skates with either Fiona or Gloria.
Step 1: Apply the Condition
We are given that Gloria and Toby are paired in Set 1.
- Set 1: (G, T)
Step 2: Make Deductions
Checking the options:
Final Answer:
\[ \boxed{\text{(B) Shigeru skates in Set 4. This is the only statement that must be true.}} \]

Two players \( A \) and \( B \) are playing a game. Player \( A \) has two available actions \( a_1 \) and \( a_2 \). Player \( B \) has two available actions \( b_1 \) and \( b_2 \). The payoff matrix arising from their actions is presented below:

Let \( p \) be the probability that player \( A \) plays action \( a_1 \) in the mixed strategy Nash equilibrium of the game.
Then the value of p is (round off to one decimal place).
Three friends, P, Q, and R, are solving a puzzle with statements:
(i) If P is a knight, Q is a knave.
(ii) If Q is a knight, R is a spy.
(iii) If R is a knight, P is a knave. Knights always tell the truth, knaves always lie, and spies sometimes tell the truth. If each friend is either a knight, knave, or spy, who is the knight?