The 31 members of the board of the Student S. Inc. are about to take a secret ballot

Question

whether to accept the merger proposal of Student G. Corp. Each member can vote to
accept the proposal, reject the proposal or to abstain. For the proposal to be accepted, 16
members must vote to accept it. All, the 31 members care about is being on the winning
side. That is, if the proposal is accepted, each member would prefer to accept it; and
if the proposal is rejected, each member would prefer to have rejected it. Find the two
Nash equilibria of this game. What would you predict the outcome will be and why?