Math
posted by Mack on .
Open Ended
Nick is starting college in the fall. She has purchased a Star Phone card for $30.00for long didtance calls. The calls cost 10 cents per minute nation wide during the daytime, 6 a.m  6 p.m
and 5 cents per minute nationwide at night, 6 p.m6a.m.
Every day Nick plans to make 2 daytime calls, each 5 minutes long, and 3 night calls, each 15 minutes long.
Will one phone card last for a week? Support answer mathematically.
What is the least # of cards nicole will need during the first 13 week semester at college? Support ansere mathematically.
I copied off of someone and therefore I don't understand how this person came up with the answer. So could you help me understand how this person came up with the answer? This is what it looks like.
2*5=10min.
15*3=45min.
Total cost per day=
Day10min*$0.10=$1.00
Night45min*$0.05=$2.25
Total cost per week is $3.25*7=$22.75
10 cards=$300
$22.75*13=$295.75

2 daytime calls = 10 min. * $0.10 = $1.00 per day
3 night calls = 45 min. * $0.05 = $2.25 per day
$2.25 + $1.00 = 3.25 cost of calls per day.
You can take it from here. We'll be glad to check your answers.