5. An individual uses the following gambling system at Las Vegas. He bets $1 that the roulette wheel will come up red. If he wins, he quits. If he loses then he makes the same bet a second time only this time he bets $2; and then regardless of the outcome, quits. Assuming that he has a probability of 1/2 of winning each bet, what is the probability that he goes home a winner? Why is this system not used by everyone?