[Solved] If the pH readings of an unknown substance is pH \(= 10.4\) , find the hydrogen ion concentration. Aggregate Demand: Aggregate demand represents the total sum of demand for all products and services in an economy, measured at a specific price level and during a particular time frame. Full Employment GDP: The level of GDP at which all available labor resources are being used in the most efficient way possible, typically associated with a low unemployment rate. C + I: Represents the sum of consumption (C) and investment (I) in an economy, indicating total expenditures on goods and services. C + S: Represents the sum of consumption (C) and savings (S), which together account for all disposable income in an economy.