math

percent means "part of one hundered" which means that 73% is 73 parts of 100 or 0.73.
You can now just multiply 13 by 0.73 and get 9.49

Guest:

percent means "part of one hundered" which means that 73% is 73 parts of 100 or 0.73.
You can now just multiply 13 by 0.73 and get 9.49

Our guest has done a slightly different question from your one.
Maybe on purpose

You can copy the technique and do your own one.