Answer:
minutes at daytime rate: 3.00
minutes at nighttime rate: $2.70
total cost of call: $8.55
Explanation:
split up the hours so you have the 5 cent charge per minute for 1 hour and you have the 3 cents a minute for an hour and a half after 8.
multiply 5 cents a minute by 60 to get the amount of money for the first hour($3.00),
next multiply 3cents a minute by an hour and a half (90 minutes) to get $2.70
next add the money together to get $5.70 and multiply that by 1.5 to get $8.55