The unit rate for "On call" is 35 cents per hour and "Talk time" is $2.50 per hour.
On call: In order to get a unit rate, the second part of the ratio must be 1. 10 divided by 10 is 1. However, what you do to the second part you must do to the first. 3.5 / 10 = .35 or 35 cents in this case.
Talk time: 1/2 an hour isn't a full hour (since we are finding the money paid per FULL HOUR). This means we must multiply 1/2 by 2 in order to get 1. However, what you do to the first part you must do to the second part. $1.25 x 2 = $2.20. $2.20 is paid every FULL hour.
