Question

Your phone plan charges you an initial fee, and then a certain amount depending on the amount of data you use. They send you periodic updates of your usage andyour current bill cost. After using 3 GB of data you owe $30. After 5 GB of data, you owe $40. What is the initial fee prior to the data usage charge?A.$15B.$5C.$2.50D.$10

Answer 1

If for 3 Gb we get a bill for $30 and for 5 Gb we get a bill of $40. It implies that every Gb costs $5, therefor the equation we have use 3 Gb is

`30=3\cdot5+b`

where b is the initial fee. Solving this for b we get that

`b=30-15=15`

so the initial fee is $15