According to the information given in the exercise, the movie is 3 hours long. and he has watched this part of it:

Then, in order to find what fraction of one hour he spent watching that movie, you need to remember the following:
-A fraction has this form:

Where "a" is the numerator and "b" is the denominator.
- To multiply fractions the procedure is:

Then, knowing the above, you can rewrite 3 hours as following:

And multiplying it by the fraction of the movie he has watched, you get:

Then:

Since he has watched 30 minutes of the movie and knowing that 1 hour has 60 minutes, you can determine that:

Therefore, the answer is:
