I am new to course hero, as this is my first question to a tutor...How do you get the time fractions? for instance in the #3. question, the time is

I am new to course hero, as this is my first question to a tutor...How do you get the time fractions? for instance in the #3. question, the time is 33/360. Why is that? Im understanding the principal and rate. Also, What is the total through maturity?