Answer:
Discounted price= $16.792
Explanation:
Giving the following information:
The extra data costs are $20.99 monthly, but they're offering 20% off that.
To calculate the discounted price, we need to use the following formula:
Discounted price= normal price*(1 - discount rate)
Discounted price= 20.99*0.8
Discounted price= $16.792