Who is asking: Other
Here is the data below
# of calls - 238
The "formula" is contained in your question. You asked for the "cost per minute" so the answer is to take the cost and divide by the number of minutes. (The language is the same as we use for speed. If you travel 100 miles in 2 hours then the average speed in "miles per hour" is 100/2 = 50 miles per hour.)
With the data you have supplied the cost per minute is $70.06/443 = 0.158 or 15.8 cents per minute.
If this data comes from an actual phone bill then the "formula" might not be this simple. For example some long distance providers charge different rates at different times of the day. Also the rate may depend on the location being called or the length of the call.I hope this helps,