This report delves into the relationship between interest rates and business investment, focusing on the impact of the Reserve Bank of Australia (RBA) lowering its official cash rate. It explains how this reduction influences business investment, aggregate demand, real GDP, and the price level. The analysis explores the inverse relationship between interest rates and investment, the role of opportunity cost, and how lower rates can stimulate economic activity. The report further examines the effects of increased business investment on macroeconomic indicators, using the aggregate demand curve to illustrate the changes in real GDP and price levels. It also discusses how the RBA's monetary policy influences investment decisions, the role of capital stock, and the impact of investment on productivity and economic growth. The report concludes by emphasizing how decreased interest rates improve cash flow, influencing overall productivity and economic activities, and highlighting the role of government in supporting business investment to enhance the nation's income.