Law of Diminishing Returns

Pretty self-explanatory law, the law of diminishing marginal returns is a theory in economics that predicts that after some optimal level of capacity is reached, adding an additional factor of production will actually result in smaller increases in output.

Applicable when it comes to school studying

5 hours 70% 10 hours 95% 30 hours - > 98%

is the 3 hours worth 3%? No right. This is where you need to find your Balance