Please give full explanation The Pew Internet and American

Please give full explanation :)

The Pew Internet and American Life Project interviewed several hundred teens (ages 12 to 17). One question asked was \"How often do you take your cell phone to school?\" Below is a two-way table of the responses by how permissive the school is with regard to cell phone use:

What percent (± 0.01) of teens from schools that forbid cell phones brought their cell phone to school every day?  %

Solution

Total number of teens whose schools forbid cell phones: 28+15+16+101 = 160

Number of teens whose school forbids cell phone and they brought their phone everyday= 101

Therefore, required percentage = 101/160 = 63.125%