Black or Red. With a $\$100.00$ bankroll I want to increase to $\$200.00$. To achieve my goal what type of bet should I make. Would I be best to make only 1 bet ($\$100.00$) or 2 bets ($\$50.00$)each or 4 bets($\$25.00$) each. How will the number of bets I make affect my odds of accomplishing my goal.
My thoughts are while it might be better to make one attempt to reach my goal making 2 bets would give me a second chance if the first one fails.
We don't need to get into any specific odds/probabilities in order to see the optimal play in a situation such as this.
Assuming you're talking about betting on black/red on a roulette wheel or pass/don't pass in craps (also known as a black/red bet) your optimal play will be to make a single bet. The house will always have the advantage on any bet you make giving you a negative expected value for all of your bets.
Due to this negative expected value, the more bets that you make, the more money the casino theoretically gets from you with each bet made. Therefore, your best bet to double up is to make a single $\$100$ bet on a black/red bet, and hope you win.
Remember to gamble responsibly.