To find the potential increase, the equation would be the amount of excess reserves (or deposits multiplied by the reserve ratio) multiplied by (100 divided by the required ratio). In this case, that would be (35 - ($200M * 0.10)) * (100/10), or (35M - 20M) * (10). This would leave 15M * 10, or $150 million in potential increase in deposits for the entire banking system.