Piecewise word problem

Question

The data plan for a smart phone costs $35 for up to 5 gigabytes of data and it costs $10 extra for each additional gigabyte, over 5, of data used.

1. write the rule for function
2. how much will it cost if 3.5 gigabytes the first month?
3. how much will it cost if you use 8 gigabytes second month?

Please help !!

Answer 1

P = $35 + $10∗g → Price per month

g - number of gigabytes over 5 gigabytes, used per month

1st month:

P₁ = $35 + $10∗0 = $35

3.5 gigabyte used

2nd month:

P₂ = $35 + $10∗3 = $75

8 gigabyte used (3 gigabytes over 5 gigabytes)