So per week, 7 hours on internet, and 13 playing games.
We can combine these two values, as they're both a part of the answer.
7 + 13 = 20
So, Gary has 5 hours a day.
7 days in a week, so 5 * 7 = 35
That means 35 hours of free time a week.
So, time spent on the internet and video games can be represented as 20/35
To find the percentage, we can just divide.
20/35 = 0.57, or 57%
57% of free time is spent playing video games