In 2016, 1 out of every 5 people under the age of 50 used a cell phone to read e-books. This means that 2 out of every 10 people under the age of 50 used a cell phone to read e-books. Also, 3 out of every 15 people under the age of 50 used a cell phone to read e-books.
Therefore, if there were x people under the age of 50 in 2016, then the number that used a cell phone to read e-books would be
1/5 × x = x/5
If there were approximately 225 million people under the age of 50 in 2016, then the number that were likely to have read an e-book on a cell phone is
