First you should:
subtract .50 from $4 for the 1st minute of the call.
Next step: divide 3.50 by .15
round 23.33 minutes to 23 minutes
Now we have 23 minutes at .15(15 cents) and 1 minute at .50(50 cents):
Mark and his sister can talk for 24 minutes.
to find out how much he will get charged simply plug in the numbers:
Multiply: Now you have
So Mark will be Charged $3.95.
If you have any questions e-mail me at Southqueensb@yahoo.com
~EVY~