Answer:
Step-by-step explanation:
The expected payoff from betting
E= Prob(win) * Payoff (win)+Prob(loose)* Payoff(loose)
Let p be the probability of win.
E = p*100+(1-p)*0 =100p
Cost of betting = $30
Betting is profitable if 100p>=30
p>=30/100
p>=0.3
If p>=0.3, then betting happens.