Answer:$99
Explanation:
You receive a 10% discount off your first cell phone bill
Monthly cell phone plan charges a flat monthly fee of $10.00 plus $0.25 per minute
If you talk on your cell phone for 400 minutes during the first month of cell phone service
Total cost on your cell phone for 400 minutes during the first month of cell phone service
= 10 + 400×0.25=$110
Discount off first cell phone bill = 10% of this total cost = 10/100 ×110
=0.1 ×110 = $11
the amount of your first cell phone bill
= total cost - discount
110-11= $99