A quarter is represented as ¼.
But ¼ of what? What is the "whole" quantity being referenced?
When speaking of money and quarters, the "whole" is one dollar, or 100 cents. Then ¼ of 100 cents is 25 cents, or a quarter.
When speaking of time, the "whole" is one hour, or 60 minutes.
Then ¼ of 60 minutes is 15 minutes, or a quarter of an hour.