The percent increase from the original cost of the entertainment system to the cost of the entertainment system using the payment plan is 12%.
<u>Step-by-step explanation</u>:
- The original cost of entertainment system = $500
- The cost using payment plan= $125+ ($72.50
6)
- cost by payment plan ⇒ 125+ 435 = $560
Percentage increase = (higher value - lower value/ lower value) 100
⇒ ((560-500)/500) 100
⇒ (60/500) 100
⇒ 0.12 100
⇒ 12%