Question:

Two friends Aditi and Raju are deciding independently whether to watch a movie or go to a music concert that evening. Both friends would prefer to spend the evening together than apart. Aditi would prefer that they watch a movie together, while Raju would prefer that they go to the concert together. The payoff matrix arising from their actions is presented below. p and (1 - p) are the probabilities that Aditi will decide in favour of the movie and concert, respectively. Similarly, q and (1 - q) are the probabilities that Raju will decide in favour of the movie and concert, respectively. Which one of the following options correctly contains all the Nash Equilibria ?
Raju
Aditi MovieConcert
Movie2,10,0
Concert0,01,2

Updated On: Aug 21, 2025
  • \((p=0,q=0);(p=1,q=1);(p=\frac{2}{3},q=\frac{1}{3})\)
  • \((p=0,q=1);(p=1,q=0);(p=\frac{2}{3},q=\frac{1}{3})\)
  • \((p=0,q=0);(p=1,q=1);(p=\frac{1}{3},q=\frac{2}{3})\)
  • \((p=0,q=1);(p=1,q=0);(p=\frac{1}{3},q=\frac{2}{3})\)
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

To find the Nash Equilibria in the problem presented, we analyze the payoff matrix for Aditi and Raju. Below is the payoff matrix corresponding to their strategy choices:
Raju
AditiMovieConcert
Movie2,10,0
Concert0,01,2
A Nash Equilibrium occurs when no player can benefit by changing their strategy unilaterally. We check each possible strategy combination:
  • (Movie, Movie): Aditi receives 2 and Raju 1. Neither can increase their payoffs by changing strategy alone since they would receive 0 otherwise (0,0 or 0,0). Hence, (0,0) is a Nash Equilibrium.
  • (Concert, Concert): Aditi receives 1 and Raju 2. Switching would give them both a payoff of 0, hence (1,1) is a Nash Equilibrium.
Next, we find the mixed strategy Nash Equilibrium by setting up the expected payoffs:
  • Aditi's expected payoff: Aditi will choose "Movie" with probability \(p\), and Raju's choice affects her payoff. Therefore, we express her expected payoff from "Movie" as:

    \(E_{Aditi}(Movie) = q \times 2 + (1-q) \times 0 = 2q\)

    From "Concert":

    \(E_{Aditi}(Concert) = q \times 0 + (1-q) \times 1 = 1-q\)

    For equilibrium, set equations equal:

    \(2q = 1-q \Rightarrow 3q = 1 \Rightarrow q = \frac{1}{3}\)

  • Raju's expected payoff: Similar expressions apply for Raju. Choosing "Movie" with probability \(q\):

    \(E_{Raju}(Movie) = p \times 1 + (1-p) \times 0 = p\)

    From "Concert":

    \(E_{Raju}(Concert) = p \times 0 + (1-p) \times 2 = 2 - 2p\)

    Equilibrium when:

    \(p = 2 - 2p \Rightarrow 3p = 2 \Rightarrow p = \frac{2}{3}\)

Thus, the mixed strategy equilibrium is \((p=\frac{2}{3}, q=\frac{1}{3})\).
Conclusively, the Nash Equilibria are at \((p=0,q=0)\), \((p=1,q=1)\), and the mixed strategy \((p=\frac{2}{3},q=\frac{1}{3})\).
Was this answer helpful?
0
0

Top Questions on Probability

View More Questions

Questions Asked in GATE XH-C1 exam

View More Questions